α1β1 Integrin/Rac1-Dependent Mesangial Invasion of Glomerular Capillaries in Alport Syndrome

Alport syndrome, hereditary glomerulonephritis with hearing loss, results from mutations in type IV collagen COL4A3, COL4A4, or COL4A5 genes. The mechanism for delayed glomerular disease onset is unknown. Comparative analysis of Alport mice and CD151 knockout mice revealed progressive accumulation of laminin 211 in the glomerular basement membrane. We show mesangial processes invading the capillary loops of both models as well as in human Alport glomeruli, as the likely source of this laminin. l-NAME salt–induced hypertension accelerated mesangial cell process invasion. Cultured mesangial cells showed reduced migratory potential when treated with either integrin-linked kinase inhibitor or Rac1 inhibitor, or by deletion of integrin α1. Treatment of Alport mice with Rac1 inhibitor or deletion of integrin α1 reduced mesangial cell process invasion of the glomerular capillary tuft. Laminin α2–deficient Alport mice show reduced mesangial process invasion, and cultured laminin α2–null cells showed reduced migratory potential, indicating a functional role for mesangial laminins in progression of Alport glomerular pathogenesis. Collectively, these findings predict a role for biomechanical insult in the induction of integrin α1β1–dependent Rac1-mediated mesangial cell process invasion of the glomerular capillary tuft as an initiation mechanism of Alport glomerular pathology.Alport syndrome is characterized by delayed-onset progressive glomerulonephritis associated with sensorineural hearing loss and retinal flecks.¹ The most common form (80%) is X-linked and caused by mutations in the type IV collagen COL4A5 gene.² The two autosomal forms of the disease account for the remaining 20% of Alport patients, and result from mutations in the COL4A3 and COL4A4 genes.³ The α3(IV), α4(IV), and α5(IV) proteins form a heterotrimer that is assembled into a subepithelial network in the glomerular basement membrane (GBM) that is physically and biochemically distinct from a subendothelial type IV collagen network comprising α1(IV) and α2(IV) heterotrimers.⁴ Mutations in any one of the three type IV collagen genes that cause Alport syndrome result in the absence of all three proteins in the GBM due to an obligatory association to form functional heterotrimers.⁵ Thus, the net result for all genetic forms of Alport syndrome is the absence of the α3(IV) α4(IV) α5(IV) subepithelial collagen network, resulting in a GBM type IV collagen network comprising only α1(IV) and α2(IV) heterotrimers.This change in basement membrane composition does not result in immediate pathology. The GBM appears to function adequately for the first few years of life and sometimes past the first decade.⁶ This delayed onset predicts a triggering mechanism for glomerular disease initiation and a theoretical window for therapeutic intervention that may arrest or significantly ameliorate Alport renal disease in its earliest stages. The activation of genes encoding GBM matrix molecules, matrix metalloproteinases (MMPs), and proinflammatory cytokines have all been linked to the progression of Alport glomerular disease. These, however, are events that occur after the onset of proteinuria, and therefore, downstream of disease initiation events.^7–11 Consistent with this notion, experiments aimed at blocking these pathways have offered only limited therapeutic benefit in mouse models for Alport syndrome.^8–10,12 One of the earliest events we have documented is the appearance of an irregular deposition of laminin 211 in the GBM of Alport mice,⁸ an observation confirmed in both Alport dogs and human patients with the disease.¹³ This laminin is normally found only in the mesangium of the glomerulus, and is not expressed in the GBM at any stage of embryonic development.¹⁴ Indeed, several other mesangial matrix proteins appear in the GBM of Alport mice, including laminin 111 and fibronectin.^15,16In the Alport glomerulus, the podocytes are exposed to GBM that has an embryonic type IV collagen composition.^17,18 This could result in altered cell signaling that may trigger the onset of the disease. It has been proposed that this type of mechanism may account for the reactivation of laminin 111 expression in podocytes,¹⁹ because laminin 111 is found in the GBM during development.¹⁴ Because the α1(IV)/α2(IV) collagen network contains significantly fewer interchain disulfide crosslinks,²⁰ and the Alport GBM is thinner than normal,²¹ the Alport GBM is likely to be more elastic, resulting in elevated biomechanical strain on the glomerular cells at their points of contact with the GBM. Consistently, glomeruli from Alport mice have been shown to have elevated deformability relative to wild-type glomeruli,²² and salt-induced hypertension has been shown to accelerate glomerular disease progression in Alport mice.²³In this work, we show that the cellular origin of GBM laminin 211 in Alport glomeruli is mesangial cell process invasion, and that deletion of laminin 211 in Alport mice ameliorates the mesangial process invasion of the glomerular capillary loops in Alport mice. Salt-mediated hypertension exacerbates this mesangial process invasion. A knockout mouse for the integrin α3β1 coreceptor CD151 also develops mesangial process invasion of the capillary loops with GBM deposition of laminin 211, demonstrating the same phenotype for a completely unrelated component of the capillary structural barrier. The CD151 knockout mouse model also shows accelerated glomerular disease progression in response to hypertension.²⁴ We show that biomechanical stretching of cultured mesangial cells induces promigratory cytokines transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF), both known to be induced in Alport glomeruli.^7,12 Inhibitor studies indicate that mesangial cell migration is mediated by integrin α1β1 signaling through the Rho GTPases RAC1 and CDC42. Consistently, integrin α1 deletion in Alport mice was previously shown to ameliorate glomerular disease progression and slow the accumulation of laminin 211 in Alport GBM.⁸ Here, we show that mesangial process invasion of the capillary loops is ameliorated in integrin α1–null Alport mice. These data define a role for biomechanical strain-mediated induction of mesangial cell process invasion as a key aspect of Alport glomerular disease initiation, and set the stage for defining novel therapeutic targets aimed at blocking this process.     

Somatic mosaicism and variant frequency detected by next-generation sequencing in X-linked Alport syndrome

X-linked Alport syndrome (XLAS) is a progressive, hereditary nephropathy. Although men with XLAS usually develop end-stage renal disease before 30 years of age, some men show a milder phenotype and develop end-stage renal disease later in life. However, the molecular mechanisms associated with this milder phenotype have not been fully identified. We genetically diagnosed 186 patients with suspected XLAS between January 2006 and August 2014. Genetic examination involved: (1) extraction and analysis of genomic DNA using PCR and direct sequencing using Sanger''s method and (2) next-generation sequencing to detect variant allele frequencies. We identified somatic mosaic variants in the type VI collagen, α5 gene (COL4A5) in four patients. Interestingly, two of these four patients with variant frequencies in kidney biopsies or urinary sediment cells of ≥50% showed hematuria and moderate proteinuria, whereas the other two with variant frequencies of <50% were asymptomatic or only had hematuria. De novo variants can occur even in asymptomatic male cases of XLAS resulting in mosaicism, with important implications for genetic counseling. This is the first study to show a tendency between the variant allele frequency and disease severity in male XLAS patients with somatic mosaic variants in COL4A5. Although this is a very rare status of somatic mosaicism, further analysis is needed to show this correlation in a larger population.     

Genetic testing and glomerular hematuria—A nephrologist's perspective

Alport syndrome is an inherited disorder of the kidneys that results from variants in three collagen IV genes—COL4A3, COL4A4, and COL4A5. Early diagnosis and pharmacologic intervention can delay the progression of chronic kidney disease and the onset of kidney failure in patients with Alport syndrome. This article describes the evolution of approaches to the diagnosis and early treatment of Alport syndrome.     

Non-visible versus visible haematuria and bladder cancer risk: a study of electronic records in primary care

Background

Diagnosis of bladder cancer relies on investigation of symptoms presented to primary care, notably visible haematuria. The importance of non-visible haematuria has never been estimated.

Aim

To estimate the risk of bladder cancer with non-visible haematuria.

Design and setting

A case–control study using UK electronic primary care medical records, including uncoded data to supplement coded records.

Method

A total of 4915 patients (aged ≥40 years) diagnosed with bladder cancer between January 2000 and December 2009 were selected from the Clinical Practice Research Datalink and matched to 21 718 controls for age, sex, and practice. Variables for visible and non-visible haematuria were derived from coded and uncoded data. Analyses used multivariable conditional logistic regression, followed by estimation of positive predictive values (PPVs) for bladder cancer using Bayes’ theorem.

Results

Non-visible haematuria (coded/uncoded data) was independently associated with bladder cancer: odds ratio (OR) 20 (95% confidence interval [CI] =12 to 33). The PPV of non-visible haematuria was 1.6% (95% CI = 1.2 to 2.1) in those aged ≥60 years and 0.8% (95% CI = 0.1 to 5.6) in 40–59-year-olds. The PPV of visible haematuria was 2.8% (95% CI = 2.5 to 3.1) and 1.2% (95% CI = 0.6 to 2.3) for the same age groups respectively, lower than those calculated using coded data alone. The proportion of records of visible haematuria in coded, rather than uncoded, format was higher in cases than in controls (P<0.002, χ² test). There was no evidence for such differential recording of non-visible haematuria by case/control status (P = 0.78), although, overall, the uncoded format was preferred (P<0.001).

Conclusion

Both non-visible and visible haematuria are associated with bladder cancer, although the visible form confers nearly twice the risk of cancer compared with the non-visible form. GPs’ style of record keeping varies by symptom and possible diagnosis.     

Novel form of X-linked nonsyndromic hearing loss with cochlear malformation caused by a mutation in the type IV collagen gene COL4A6

Hereditary hearing loss is the most common human sensorineural disorder. Genetic causes are highly heterogeneous, with mutations detected in >40 genes associated with nonsyndromic hearing loss, to date. Whereas autosomal recessive and autosomal dominant inheritance is prevalent, X-linked forms of nonsyndromic hearing impairment are extremely rare. Here, we present a Hungarian three-generation family with X-linked nonsyndromic congenital hearing loss and the underlying genetic defect. Next-generation sequencing and subsequent segregation analysis detected a missense mutation (c.1771G>A, p.Gly591Ser) in the type IV collagen gene COL4A6 in all affected family members. Bioinformatic analysis and expression studies support this substitution as being causative. COL4A6 encodes the alpha-6 chain of type IV collagen of basal membranes, which forms a heterotrimer with two alpha-5 chains encoded by COL4A5. Whereas mutations in COL4A5 and contiguous X-chromosomal deletions involving COL4A5 and COL4A6 are associated with X-linked Alport syndrome, a nephropathy associated with deafness and cataract, mutations in COL4A6 alone have not been related to any hereditary disease so far. Moreover, our index patient and other affected family members show normal renal and ocular function, which is not consistent with Alport syndrome, but with a nonsyndromic type of hearing loss. In situ hybridization and immunostaining demonstrated expression of the COL4A6 homologs in the otic vesicle of the zebrafish and in the murine inner ear, supporting its role in normal ear development and function. In conclusion, our results suggest COL4A6 as being the fourth gene associated with X-linked nonsyndromic hearing loss.     

Appropriateness of antidepressant prescribing: an observational study in a Scottish primary-care setting

Background

Since the 1990s, Scottish community-based antidepressant prescribing has increased substantially.

Aim

To assess whether GPs prescribe antidepressants appropriately.

Design of study

Observational study of adults (aged ≥16 years) screened with the Hospital Anxiety and Depression Scale (HADS) attending a GP.

Setting

Four practices in Grampian, Scotland.

Method

Patients (n = 898) completed the HADS, and GPs independently estimated depression status. Notes were scrutinised for evidence of antidepressant use, and the appropriateness of prescribing was assessed.

Results

A total of 237 (26%) participants had HADS scores indicating ‘possible’ (15%) or ‘probable’ (11%) depression. The proportion of participants rated as depressed by their GP differed significantly by HADS depression subscale scores. Odds ratio for ‘possible’ versus ‘no’ depression was 3.54 (95% confidence interval [CI] = 2.17 to 5.76, P<0.001); and for ‘probable’ versus ‘possible’ depression was 3.59 (95% CI = 2.06 to 6.26, P<0.001). Similarly, the proportion of participants receiving antidepressants differed significantly by HADS score. Odds ratio for ‘possible’ versus ‘no’ depression was 2.79 (95% CI = 1.70 to 4.58, P<0.001); and for ‘probable’ versus ‘possible’ was 2.12 (95% CI = 1.21 to 3.70, P = 0.009). In 101 participants with ‘probable’ depression, GPs recognised 53 (52%) participants as having a clinically significant depression. Inappropriate initiation of antidepressant treatment occurred very infrequently. Prescribing to participants who were not symptomatic was accounted for by the treatment of pain, anxiety, or relapse prevention, and for ongoing treatment of previously identified depression.

Conclusion

There was little evidence of prescribing without relevant indication. Around half of patients with significant symptoms were not identified by their GP as suffering from a depressive disorder: this varied inversely with severity ratings. Rather than prescribing indiscriminately (as has been widely assumed), it is likely that GPs are initiating antidepressant treatment conservatively.     

Stakeholder views on opportunistic genomic screening in the Netherlands: a qualitative study

Genome sequencing can be used to actively search for genetic variants unrelated to the initial clinical question. While such ‘opportunistic genomic screening’ (OGS) has been proposed in the USA, a European discussion on the ethics of OGS is only starting. Should testing for selected ‘secondary findings’ be offered to patients who need genetic sequencing? Using focus groups and interviews, we explored views on OGS in adults and minors from three perspectives: policy experts (n = 9), health professionals (n = 8) and patient representatives (n = 7). A thematic approach was used to analyze the data. There was consensus that OGS should be evaluated in terms of the classical ‘screening’ framework, rather than as a form of ‘good patient care’. Accordingly, stakeholders agreed that professionals do not have a ‘fiduciary duty’ to look for secondary findings. Adding screening to clinical care was only conceivable with the patient’s informed consent. In general, stakeholders were reluctant towards OGS. Arguments for regarding OGS being premature included lack of evidence regarding its clinical utility, also in view of uncertainties regarding general population penetrance, and concerns about both its psychosocial impact and respect for autonomy. All groups agreed that OGS means unequal access, which was seen as problematic. Yet, despite their concerns, stakeholders felt that offering screening for certain actionable pathogenic variants with known high penetrance could potentially be valuable in certain contexts for both adults and minors. Pharmacogenetic variants were regarded as a category by itself, for which OGS could potentially be beneficial.Subject terms: Medical ethics, Ethics     

Three novel COL4A4 mutations resulting in stop codons and their clinical effects in autosomal recessive Alport syndrome

Autosomal recessive Alport syndrome is caused by mutations in the COL4A3 and COL4A4 genes which code for the alpha3 and alpha4 chains of type IV collagen. These mutations result in haematuria, progressive renal impairment and often hearing loss, lenticonus and retinopathy. We describe here the mutations demonstrated by screening the 47 coding exons of the COL4A4 gene in six families with autosomal recessive Alport syndrome using PCR-single stranded conformational polymorphism (SSCP) analysis. Six sequence variants were identified. These included three novel mutations (2846delG, 2952delG and S969X) in exons 30 - 32 that all resulted in premature stop codons. These mutations were demonstrated in the heterozygous form in 3 families, and the S969X mutation was also present in the homozygous form in one of the two consanguinous families. These three mutations accounted for 40% (4/10) of the total mutant alleles in the six families studied. Six of the seven (86%) individuals with autosomal recessive Alport syndrome who had these mutations in the compound heterozygous or homozygous forms developed renal failure in adulthood, as well as hearing loss and ocular abnormalities. Haematuria was present in 15 of the 17 (88%) heterozygous mutation carriers. The other non-pathogenic sequence variants noted in COL4A4 included a nonglycine missense variant (L1004P), an intronic variant (4731-8 T>C) and a neutral polymorphism (V1516V).     

Alport syndrome: impact of digenic inheritance in patients management

Alport syndrome (ATS) is a genetically heterogeneous nephropathy with considerable phenotypic variability and different transmission patterns, including monogenic (X‐linked/autosomal) and digenic inheritance (DI). Here we present a new series of families with DI and we discuss the consequences for genetic counseling and risk assessment. Out of five families harboring variants in more than one COL4 gene detected by next generation sequencing (NGS), minigene‐splicing assay allowed us to identify four as true digenic. Two families showed COL4A3/A4 mutations in cis, mimicking an autosomal dominant inheritance with a more severe phenotype and one showed COL4A3/A4 mutations in trans, mimicking an autosomal recessive inheritance with a less severe phenotype. In a fourth family, a de novo mutation (COL4A5) combined with an inherited mutation (COL4A3) triggered a more severe phenotype. A fifth family, predicted digenic on the basis of silico tools, rather showed monogenic X‐linked inheritance due to a hypomorphic mutation, in accordance with a milder phenotype. In conclusion, this study highlights the impact of DI in ATS and explains the associated atypical presentations. More complex inheritance should be therefore considered when reviewing prognosis and recurrence risks. On the other side, these findings emphasize the importance to accompany NGS with splicing assays in order to avoid erroneous identification of at risk members.     

Characterisation of the human GFRalpha-3 locus and investigation of the gene in Hirschsprung disease

BACKGROUND—The GDNF family receptor alpha (GFRα) proteins are extracellular cell surface bound molecules that act as adapters in binding of the GDNF family of soluble neurotrophic factors to the RET receptor. These molecules are essential for development of many neural crest derived cell types and the kidney. Mutations in RET and in two members of the GDNF ligand family are associated with Hirschsprung disease (HSCR), a congenital absence of the enteric ganglia. Members of the GFRα family are also candidates for HSCR mutations. One such gene is GFRα-3, which is expressed in the peripheral nervous system and developing nerves.
OBJECTIVE—We have characterised the structure of the human GFRα-3 locus and investigated the gene for sequence variants in a panel of HSCR patients.
METHODS—Long range PCR or subcloning of PAC clones was used to investigate GFRα-3 intron-exon boundaries. A combination of single strand conformation polymorphism (SSCP) analysis and direct sequencing was used to investigate GFRα-3 sequence variants.
RESULTS—GFRα-3 spans eight coding exons and has a gene structure and organisation similar to that of GFRα-1. We identified three polymorphic variants in GFRα-3 in a normal control population, a subset of which also occurred in HSCR patients. We did not detect any sequence variants within the coding sequence of GFRα-3. We found a base substitution in the 5' UTR of GFRα-3, 15 base pairs upstream of the translation start site. A second substitution was identified in intron 4 (IVS4-30G>A) between the splice branch site and the splice acceptor site. The final variant was a 2 base pair insertion within the splice donor consensus sequence of exon 7 (IVS7+4ins GG).
CONCLUSIONS—We did not detect any correlation between variants of GFRα-3 and the HSCR phenotype. Our data suggest that mutations of this gene are not a cause of HSCR.


Keywords: GFRα-3; Hirschsprung disease; RET     

Trends of Internet Search Volumes for Major Depressive Disorder Symptoms During the COVID-19 Pandemic in Korea: An Interrupted Time-Series Analysis

BackgroundThe effect of coronavirus disease 2019 (COVID-19) pandemic on public mental health has been increasing. Additionally, the underlying psychological stressors remain unexplored, and few studies have been conducted nationally on the social distancing measures. Therefore, the present study aimed to identify the psychological impacts of the implementation of social distancing measures by analyzing the Internet search trends of major depressive disorder (MDD) symptoms.MethodsUsing Naver^® Trends’ relative search volumes (RSVs), we analyzed the average search volumes and trend changes of 16 terms, adopted from the Diagnostic and Statistical Manual of Mental Disorders-5 criteria for diagnosing MDD. An interrupted time-series analysis was performed using the data from January 1, 2016 to December 31, 2020. Furthermore, changes in RSVs, according to the intensity of the social distancing measures implemented from January 1 to December 31, 2020, were determined using Wilcoxon rank sum tests.ResultsOf the 16 terms, the search trends of ‘feeling guilty’ (P < 0.001) and ‘wanting to die’ (P = 0.002) showed a significant increase as of February 29, 2020, when the social distancing measures were officially implemented. Additionally, the average search volumes for ‘hopelessness’ (P = 0.003), ‘sexual desire’ (P < 0.001), ‘insomnia’ (P = 0.002), ‘hypersomnia’ (P < 0.001), ‘restlessness’ (P < 0.001), and ‘feeling lethargic’ (P < 0.001) increased significantly. Moreover, gender analysis showed that the average search volume of ‘depressed mood’ (P = 0.033) and the trend of ‘impaired concentration’ (P < 0.001) increased in males only. However, the average search volume of ‘feeling lethargic’ (P = 0.001) and the trend of ‘feeling guilty’ (P = 0.001) increased in females only. The average search volumes for ‘depressed mood’ (P < 0.001), ‘impaired concentration’ (P = 0.038), and ‘indecisiveness’ (P < 0.001) were significantly higher during the enforcement of level 2 or higher social distancing measures.ConclusionOur results reported the negative effect of COVID-19 preventive measures on public mental health in South Korea, especially for MDD symptoms. Moreover, the findings suggested the utility of Naver Trends as a feasible big data source to assess future mental health crises.     

The Swiss National Registry for Primary Immunodeficiencies: report on the first 6 years’ activity from 2008 to 2014

The Swiss National Registry for Primary Immunodeficiency Disorders (PID) was established in 2008, constituting a nationwide network of paediatric and adult departments involved in the care of patients with PID at university medical centres, affiliated teaching hospitals and medical institutions. The registry collects anonymized clinical and genetic information on PID patients and is set up within the framework of the European database for PID, run by the European Society of Immunodeficiency Diseases. To date, a total of 348 patients are registered in Switzerland, indicating an estimated minimal prevalence of 4·2 patients per 100 000 inhabitants. Distribution of different PID categories, age and gender are similar to the European cohort of currently 19 091 registered patients: ‘predominantly antibody disorders’ are the most common diseases observed (n = 217/348, 62%), followed by ‘phagocytic disorders’ (n = 31/348, 9%). As expected, ‘predominantly antibody disorders’ are more prevalent in adults than in children (78 versus 31%). Within this category, ‘common variable immunodeficiency disorder’ (CVID) is the most prevalent PID (n = 98/217, 45%), followed by ‘other hypogammaglobulinaemias’ (i.e. a group of non-classified hypogammaglobulinaemias) (n = 54/217, 25%). Among ‘phagocytic disorders’, ‘chronic granulomatous disease’ is the most prevalent PID (n = 27/31, 87%). The diagnostic delay between onset of symptoms and diagnosis is high, with a median of 6 years for CVID and more than 3 years for ‘other hypogammaglobulinaemias’.     

Alternative splicing in the variable domain of CaMKIIβ affects the level of F-actin association in developing neurons

The Ca²⁺/calmodulin (CaM)-dependent protein kinase II (CaMKII) β has an essential function in dendritic spines via binding to and reorganization of the actin cytoskeleton during plasticity events not shared by CaMKIIα isoform. CaMKIIβ and CaMKIIα isoforms have remarkable structural differences within the variable region. Three exons (E1, E3, and E4) are present in CaMKIIβ but not in CaMKIIα gene. Four splice variants of CaMKIIβ isoforms (CaMKIIβ, β’, βe and β’e) were discovered in embryonic and adult brains. Exons E1 (lacked in βe and β’e) and E4 (lacked in β’ and β’e) are subject to differential alternative splicing. We hypothesized that the sequences encoded by exons E1, E3, and/or E4 are involved in CaMKIIβ-specific bundling to the F-actin cytoskeleton. We tested the colocalization and association of these CaMKIIβ variants within an F-actin-rich structure (microspike) in CaMKIIα free embryonic day 18 (E-18) rat cortical neurons. Our results showed that CaMKIIβ and CaMKIIβ’ containing exon E1 displayed an association with F-actin, while CaMKIIβe and CaMKIIβ’e lacking E1 did not. Moreover, CaMKIIβ’ lacking exon E4 but having E1 showed decreased actin bindingcapacity compared to WT CaMKIIβ. This suggested E1 is required for the association between CaMKIIβ and F-actin, while E4 assists CaMKIIβ to associate with F-actin better. Thus, alternative splicing of CaMKIIβ variants in developing neurons may serve as a developmental switch for actin cytoskeleton-associated isoforms and therefore correlated with dendritic arborization and synapse formation during LTP.     

Glycine to tryptophan substitution in type I collagen in a patient with OI type III: a unique collagen mutation

We report a unique glycine substitution in type I collagen and highlight the clinical and biochemical consequences. The proband is a 9 year old Turkish boy with severely deforming osteogenesis imperfecta (OI). Biochemical analysis of (pro) collagen type I from a skin fibroblast culture showed both normal and overmodified α chains. Molecular analysis showed a G>T transversion in the COL1A2 gene, resulting in the substitution of glycine by tryptophan at position 277 of the α2(I) collagen chain. Glycine substitutions in type I collagen are the most frequent cause of the severe and lethal forms of OI. The phenotypic severity varies according to the nature and localisation of the mutation. Substitutions of glycine by tryptophan, which is the most voluminous amino acid, have not yet been identified in type I collagen or any other fibrillar collagen. The severe, though non-lethal OI phenotype associated with this mutation may appear surprising in view of the huge size of the tryptophan residue. The fact that the mutation resides within a so called "non-lethal" region of the α2(I) collagen chain supports a regional model in phenotypic severity for α2(I) collagen mutations, in which the phenotype is determined primarily by the nature of the collagen domain rather than the type of glycine substitution involved.


Keywords: osteogenesis imperfecta; COL1A2; tryptophan; collagen     

Case finding for chronic obstructive pulmonary disease in primary care: a pilot randomised controlled trial

Background

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality. However, much of the disease burden remains undiagnosed.

Aim

To compare the yield and cost effectiveness of two COPD case-finding approaches in primary care.

Design and setting

Pilot randomised controlled trial in two general practices in the West Midlands, UK.

Method

A total of 1634 ever-smokers aged 35–79 years with no history of COPD or asthma were randomised into either a ‘targeted’ or ‘opportunistic’ case-finding arm. Respiratory questionnaires were posted to patients in the ‘targeted’ arm and provided to patients in the ‘opportunistic’ arm at routine GP appointments. Those reporting at least one chronic respiratory symptom were invited for spirometry. COPD was defined as pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC)<0.7 and FEV1<80% of predicted. Primary outcomes were the difference in the proportion of patients diagnosed with COPD and the cost per case detected.

Results

Twenty-six per cent (212/815) in the ‘targeted’ and 13.6% (111/819) in the ‘opportunistic’ arm responded to the questionnaire and 78.3% (166/212) and 73.0% (81/111), respectively, reported symptoms; 1.2% (10/815) and 0.7% (6/819) of patients in the ‘targeted’ and ‘opportunistic’ arms were diagnosed with COPD (difference in proportions = 0.5% [95% confidence interval {CI} = –0.5% to 3.08%]). Over a 12-month period, the ‘opportunistic’ case-finding yield could be improved to 1.95% (95% CI = 1.0% to 2.9%). The cost-per case detected was £424.56 in the ‘targeted’ and £242.20 in the ‘opportunistic’ arm.

Conclusion

Opportunistic case finding may be more effective and cost effective than targeting patients with a postal questionnaire alone. A larger randomised controlled trial with adequate sample size is required to test this.     

Patient experience and the role of postgraduate GP training: a cross-sectional analysis of national Patient Survey data in England

Background

Quality indicators for primary care focus predominantly on the public health model and organisational measures. Patient experience is an important dimension of quality. Accreditation for GP training practices requires demonstration of a series of attributes including patient-centred care.

Aim

The national GP Patient Survey (GPPS) was used to determine the characteristics of general practices scoring highly in responses relating to the professional skills and characteristics of doctors. Specifically, to determine whether active participation in postgraduate GP training was associated with more positive experiences of care.

Design and setting

Retrospective cross-sectional study in general practices in England.

Method

Data were obtained from the national QOF dataset for England, 2011/12 (8164 general practices); the GPPS in 2012 (2.7 million questionnaires in England; response rate 36%); general practice and demographic characteristics. Sensitivity analyses included local data validated by practice inspections. Outcome measures: multilevel regression models adjusted for clustering.

Results

GP training practice status (29% of practices) was a significant predictor of positive GPPS responses to all questions in the ‘doctor care’ (n = 6) and ‘overall satisfaction’ (n = 2) domains but not to any of the ‘nurse care’ or ‘out-of-hours’ domain questions. The findings were supported by the sensitivity analyses. Other positive determinants were: smaller practice and individual GP list sizes, more older patients, lower social deprivation and fewer ethnic minority patients.

Conclusion

Based on GPPS responses, doctors in GP training practices appeared to offer more patient-centred care with patients reporting more positively on attributes of doctors such as ‘listening’ or ‘care and concern’.     

A founder mutation in COL4A3 causes autosomal recessive Alport syndrome in the Ashkenazi Jewish population

Alport syndrome is an inherited progressive nephropathy arising from mutations in the type IV collagen genes, COL4A3, COL4A4, and COL4A5. Symptoms also include sensorineural hearing loss and ocular lesions. We determined the molecular basis of Alport syndrome in a non‐consanguineous Ashkenazi Jewish family with multiple affected females using linkage analysis and next generation sequencing. We identified a homozygous COL4A3 mutation, c.40_63del, in affected individuals with mutant alleles inherited from each parent on partially conserved haplotypes. Large‐scale population screening of 2017 unrelated Ashkenazi Jewish samples revealed a carrier frequency of 1 in 183 indicating that COL4A3 c.40_63del is a founder mutation which may be a common cause of Alport syndrome in this population. Additionally, we determined that heterozygous mutation carriers in this family do not meet criteria for a diagnosis of Thin Basement Membrane Nephropathy and concluded that carriers of c.40_63del are not likely to develop benign familial hematuria.