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     

Neuroanatomical associations of the Edinburgh cognitive and Behavioural ALS screen (ECAS)

Brain Imaging and Behavior - Cognitive impairment is now recognized in a subset of patients with amyotrophic lateral sclerosis (ALS). The objective of the study was to identify group differences...     

Irreversible brain injury following status epilepticus

Described here is a patient with medically intractable generalized epilepsy who developed status epilepticus (SE) affecting his right cerebral hemisphere for about 48 hours, which led to irreversible injury to that hemisphere. His partial SE did not respond to the first-line therapies, repeated doses of midazolam, or continuous intravenous infusion of propofol. Extensive investigations failed to find a cause of his SE except for a low serum valproic acid. A minor trauma that he suffered 1 week prior to his SE was of questionable significance. Neurological examination, neuropsychological testing, electroencephalography, and magnetic resonance imaging all demonstrated striking abnormalities limited to the affected cerebral hemisphere that did not resolve with repeated testing. This case illustrates permanent focal brain injury following prolonged partial SE in a patient with previously known generalized seizure disorder.     

An enriched-enrolment,randomized withdrawal,flexible-dose,double-blind,placebo-controlled,parallel assignment efficacy study of nabilone as adjuvant in the treatment of diabetic peripheral neuropathic pain

Cannabinoids are emerging as potential options for neuropathic pain treatment. This study evaluated an oral cannabinoid, nabilone, in the treatment of refractory human diabetic peripheral neuropathic pain (DPN). We performed a single-center, randomized, double-blind, placebo-controlled, flexible-dose study with an enriched enrolment randomized withdrawal design. DPN subjects with a pain score ?4 (0-10 scale) continued regular pain medications and were administered single-blinded adjuvant nabilone for 4 weeks. Subjects achieving ?30% pain relief (26/37) were then randomized and treated with either flexible-dose nabilone 1-4 mg/day (n = 13) or placebo (n = 13) in a further 5-week double-blind treatment period, with 30% (11/37) of subjects deemed run-in-phase nabilone nonresponders. For nabilone run-in-phase responders, there was an improvement in the change in mean end-point neuropathic pain vs placebo (mean treatment reduction of 1.27; 95% confidence interval 2.29-0.25, P = 0.02), with an average nabilone dose at end point of 2.9 ± 1.1 mg/day, and improvements from baseline for the anxiety subscale of the Hospital Anxiety and Depression Scale, the Medical Outcomes Study sleep scale problems index, and the European Quality of Life-5-Domains index score (each P < 0.05). Nabilone run-in-phase responders reported greater global end-point improvement with nabilone than with placebo (100% vs 31%; P < 0.05). Medication-related confusion led to discontinuation in 2/37 subjects during single-blind nabilone treatment. Potential unmasking occurred in 62% of both groups. Flexible-dose nabilone 1-4 mg/day was effective in relieving DPN symptoms, improving disturbed sleep, quality of life, and overall patient status. Nabilone was well tolerated and successful as adjuvant in patients with DPN.     

New derivatives of 2-carboxychromanone-4 as potential antiinflammatory drugs. I. Cis-and trans-beta-2,4-dihydroxybenzoylacrylic acids and their derivatives.

Proof is presented that the product of the reaction of resorcin and maleic anhydride in the presence of aluminum chloride in ethylene chloride solutions is cis-beta-2,4-dihydroxybenzoylacrylic acid (I). Cis and trans acids (I and II) were isomerized to 2-carboxy-7-hydroxychromanone-4(III). Reactions of acetylation of compounds I, II and III were studied.     

Distinct patterns of progressive gray and white matter degeneration in amyotrophic lateral sclerosis

Progressive cerebral degeneration in amyotrophic lateral sclerosis (ALS) remains poorly understood. Here, three‐dimensional (3D) texture analysis was used to study longitudinal gray and white matter cerebral degeneration in ALS from routine T1‐weighted magnetic resonance imaging (MRI). Participants were included from the Canadian ALS Neuroimaging Consortium (CALSNIC) who underwent up to three clinical assessments and MRI at four‐month intervals, up to 8 months after baseline (T ₀). Three‐dimensional maps of the texture feature autocorrelation were computed from T1‐weighted images. One hundred and nineteen controls and 137 ALS patients were included, with 81 controls and 84 ALS patients returning for at least one follow‐up. At baseline, texture changes in ALS patients were detected in the motor cortex, corticospinal tract, insular cortex, and bilateral frontal and temporal white matter compared to controls. Longitudinal comparison of texture maps between T ₀ and T _max (last follow‐up visit) within ALS patients showed progressive texture alterations in the temporal white matter, insula, and internal capsule. Additionally, when compared to controls, ALS patients had greater texture changes in the frontal and temporal structures at T _max than at T ₀. In subgroup analysis, slow progressing ALS patients had greater progressive texture change in the internal capsule than the fast progressing patients. Contrastingly, fast progressing patients had greater progressive texture changes in the precentral gyrus. These findings suggest that the characteristic longitudinal gray matter pathology in ALS is the progressive involvement of frontotemporal regions rather than a worsening pathology within the motor cortex, and that phenotypic variability is associated with distinct progressive spatial pathology.

In this study, we use MRI texture analysis to detect progressive cerebral degeneration in amyotrophic lateral sclerosis (ALS). Here, we demonstrate distinct spatiotemporal patterns of degeneration related to clinical phenotypes in patients with ALS.     

High diagnostic yield and novel variants in very late-onset spasticity

Hereditary spastic paraplegias (HSPs) are a diverse group of genetic conditions with variable severity and onset age. From a neurogenetic clinic, we identified 14 patients with very late-onset HSP, with symptoms starting after the age of 35. In this cohort, sequencing of known genetic causes was performed using clinically available HSP sequencing panels. We identified 4 patients with mutations in SPG7 and 3 patients with SPAST mutations, representing 50% of the cohort and indicating a very high diagnostic yield. In the SPG7 group, we identified novel variants in two patients. We have also identified two novel mutations in the SPAST group. We present sequencing data from cDNA and RT-qPCR to support the pathogenicity of these variants, and provide observations regarding the poor genotype-phenotype correlation in these conditions that should be the subject of future study.     

Phenotype of combined Duchenne and facioscapulohumeral muscular dystrophy

This case report describes a young boy with concomitant genetically-confirmed Duchenne muscular dystrophy and facioscapulohumeral muscular dystrophy with a novel dystrophin mutation in exon 6 and a D4Z4 fragment of 31 kb. This child presented with a more severe phenotype than expected for either individual disease process and underscores the role for thorough diagnostic investigation in identifying atypical clinical presentations.