Clinical diagnosis of the Usher syndromes

The Usher syndromes are genetically distinct disorders which share specific phenotypic characteristics. This paper describes a set of clinical criteria recommended for the diagnosis of Usher syndrome type I and Usher syndrome type II. These criteria have been adopted by the Usher Syndrome Consortium and are used in studies reported by members of this Consortium. © 1994 Wiley-Liss, Inc.     

Mutation profile of the MYO7A gene in Spanish patients with Usher syndrome type I

Usher syndrome type I is the most severe form of Usher syndrome. It is an autosomal recessive disorder characterized by profound congenital sensorineural deafness, retinitis pigmentosa, and vestibular abnormalities. Mutations in the myosin VIIA gene (MYO7A) are responsible for Usher syndrome type 1B (USH1B). This gene is thought to bear greatest responsibility for USH1 and, depending on the study, has been reported to account for between 24% and 59% of USH1 cases. In this report a mutation screening of the MYO7A gene was carried out in a series of 48 unrelated USH1 families using single strand conformation polymorphism analysis (SSCP) and direct sequencing of those fragments showed an abnormal electrophoretic pattern. Twenty-five mutations were identified in 23 out of the 48 families studied (47.9%). Twelve of these mutations were novel, including five missense mutations, three premature stop codons, three frameshift, and one putative splice-site mutation. Based on our results we can conclude there is an absence of hot spot mutations in the MYO7A gene and that this gene plays a major role in Usher syndrome.     

Mutation profile of the CDH23 gene in 56 probands with Usher syndrome type I

Mutations in the human gene encoding cadherin23 (CDH23) cause Usher syndrome type 1D (USH1D) and nonsyndromic hearing loss. Individuals with Usher syndrome type I have profound congenital deafness, vestibular areflexia and usually begin to exhibit signs of RP in early adolescence. In the present study, we carried out the mutation analysis in all 69 exons of the CDH23 gene in 56 Usher type 1 probands already screened for mutations in MYO7A. A total of 18 of 56 subjects (32.1%) were observed to have one or two CDH23 variants that are presumed to be pathologic. Twenty one different pathologic genome variants were observed of which 15 were novel. Out of a total of 112 alleles, 31 (27.7%) were considered pathologic. Based on our results it is estimated that about 20% of patients with Usher syndrome type I have CDH23 mutations.     

Usher syndrome in four Norwegian counties

Among 89 probands selected for tapeto-retinal degeneration, 18 (20%) were given the diagnosis of Usher syndrome. Among the relatives of the probands another 10 cases of Usher syndrome were found. The distribution on type diagnoses was: Usher syndrome type I: 14 cases, type II: 10 cases and type III: four cases. The pattern of inheritance was autosomal recessive for 12 families, and the remaining six probands were solitary cases without consanguinity between the parents. There was a high intrafamiliar correlation with respect to hearing function, indicating genetic heterogeneity in Usher syndrome. Obligate heterozygotes did not demonstrate heterozygote manifestation. One man with Usher syndrome type I was psychotic, the remaining 27 did not demonstrate serious psychic disturbances. Atactic gait was not observed, though vestibular response was abolished in three patients with Usher syndrome type I. Three patients with type II and one person with type III had normal vestibular response. The prognosis for visual function was not highly correlated to the type diagnosis or to the age when hemeralopia was first noticed. Visual function was good before 30 years of age and bad in most patients after the age of 50.     

染色体核型异常所致反复流产的分析

为探讨染色体核型异常与反复流产的关系,对325例反复流产患者应用G、C显带技术进行了染色体核型分析.结果显示,325例反复流产患者中,染色体畸变14例,异常检出率为4.31％;其中数目异常7例(50％),结构异常6例(42.86％),复合异常1例(7.14％).由此可见,染色体异常是导致妊娠妇女反复流产的重要因素.     

Neurovascular abnormalities in patients with Loeys-Dietz syndrome type III

The aim of this article is to describe neurovascular findings in patients with Loeys Dietz syndrome type III and their possible clinical impact. Loeys Dietz syndrome type III, caused by pathogenic SMAD3 variants, is an autosomal dominant syndrome characterized by aneurysms and arterial tortuosity in combination with osteoarthritis. Neurovascular abnormalities have been described in other heritable aortic syndromes, however, reliable data in Loeys Dietz syndrome type III is missing.In our tertiary center, all adult patients with confirmed Loeys Dietz syndrome type III are followed in a standardized aorta outpatient clinic including Computed Tomography Angiography (CTA) of the head and neck region at baseline and (tri) yearly during follow-up. We performed an analysis of the neurovascular imaging findings and clinical follow-up. The primary outcome was a combined endpoint of mortality, dissection, cerebral vascular event and intervention. In addition, tortuosity and vascular growth were assessed. In total 26 patients (mean age 38.4 years, 38.5% males) underwent 102 (mean 3.9 (1-8) per patient) neurovascular Computed Tomography Angiography scans between 2010 and 2021. In 84.6% some form of neurovascular abnormality was found. The abnormalities at baseline were aneurysm (26.9%) dissection flap (7.7%), arterial tortuosity (61.5%), arterial coiling (23.1%) and arterial kinking (3.8%). During follow up (mean 8.85 (1-11) years) one patient suffered from sudden death and one patient needed a neuro-radiological intervention. No cerebral bleeding or stroke occurred.In conclusion, neurovascular imaging in Loeys Dietz syndrome type III patients revealed abnormalities such as aneurysm, tortuosity, coiling and kinking in the vast majority of patients, but clinical events were rare. Neurovascular screening and follow up is advised in all Loeys Dietz syndrome type III patients.     

Structural malformations of the brain,eye, and pituitary gland in PHACE syndrome

PHACE syndrome is the association of segmental facial hemangiomas with congenital arterial, brain, cardiac, and ocular anomalies. Structural brain malformations affect 41–52% of PHACE patients and can be associated with focal neurologic deficits, developmental delays, and/or intellectual disability. To better characterize the spectrum of structural brain and other intracranial anomalies in PHACE syndrome, MRI scans of the head/neck were retrospectively reviewed in 55 patients from the PHACE Syndrome International Clinical Registry and Genetic Repository. All registry patients with a diagnosis of definite PHACE syndrome who had MRI scans of satisfactory quality were included. Of 55 patients, 34 (62%) demonstrated ≥1 non‐vascular intracranial anomaly; structural brain malformations were present in 19 (35%). There was no difference in the prevalence of brain anomalies between genders. Brain anomalies were more likely in patients with S1 and/or S2 distribution of facial hemangioma. The most common structural brain defects were cerebellar hypoplasia (25%) and fourth ventricle abnormalities (13%). Dandy–Walker complex and malformations of cortical development were present in 9% and 7%, respectively. Extra‐axial findings such as pituitary anomalies (18%) and intracranial hemangiomas (18%) were also observed. Six patients (11%) had anomalies of the globes or optic nerve/chiasm detectable on MRI. Brain malformations comprise a diverse group of structural developmental anomalies that are common in patients with PHACE syndrome. Along with brain malformations, numerous abnormalities of the pituitary, meninges, and globes were observed, highlighting the need for careful radiologic assessment of these structures in the neuroimaging workup for PHACE syndrome.     

Homozygosity mapping to the USH2A locus in two isolated populations

Usher syndrome is a group of autosomal recessive disorders characterised by progressive visual loss from retinitis pigmentosa and moderate to severe sensorineural hearing loss. Usher syndrome is estimated to account for 6-10% of all congenital sensorineural hearing loss. A gene locus in Usher type II (USH2) families has been assigned to a small region on chromosome 1q41 called the UHS2A locus. We have investigated two families with Usher syndrome from different isolated populations. One family is a Norwegian Saami family and the second family is from the Cayman Islands. They both come from relatively isolated populations and are inbred families suitable for linkage analysis. A lod score of 3.09 and 7.65 at zero recombination was reached respectively in the two families with two point linkage analysis to the USH2A locus on 1q41. Additional homozygosity mapping of the affected subjects concluded with a candidate region of 6.1 Mb. This region spans the previously published candidate region in USH2A. Our study emphasises that the mapped gene for USH2 is also involved in patients from other populations and will have implications for future mutation analysis once the USH2A gene is cloned.     

Clinical and genetic studies in Spanish patients with Usher syndrome type II: description of new mutations and evidence for a lack of genotype--phenotype correlation

Patients with Usher syndrome type II (USH2) show moderate-to-severe hearing loss (HL), retinitis pigmentosa and normal vestibular function. The progression of HL remains controversial. To evaluate whether a phenotype-genotype correlation exists regarding the issue of progression of HL, only USH2 patients with a defined genotype were selected. Ophthalmologic, vestibular and audiometric examination along with a mutation analysis of the USH2A gene (exons 1--21) was performed in twenty-eight Spanish USH2 patients. Ten different pathogenic mutations and 17 sequence variants not associated with the disease were found. Six of the 10 mutations are novel. Disease alleles were identified in 13 of the 28 families tested. Eight of these 13 families had a mutation found in both alleles. In the other five families, only one mutation was identified. The phenotypic data provide evidence for the existence of phenotypic differences between patients with the same genotype. These differences were observed at both the interfamilial and intrafamilial levels.     

Clinical findings in obligate carriers of type I Usher syndrome

Seventeen obligate carriers from nine families with autosomal recessive Usher syndrome type I underwent otological, audiological, vestibular, and ophthalmological examination in order to identify possible manifestations of heterozygosity. Linkage studies were performed and six families showed linkage to chromosome region 11q13.5 while 3 families have so far failed to show linkage to the candidate regions. Eight obligate carriers had an abnormal puretone audiogram. Two different audiometric patterns could be distinguished when hearing loss was corrected for age and sex. Four carriers (24%) had significant sensorineural hearing loss (SNHL) which increased at higher frequencies. The other 13 carriers had SNHL of about 10 dB at 0.25 and 0.5 kHz, but less at higher frequencies. Vestibular findings were generally normal. Electrooculography demonstrated a significant lower mean light peak/dark trough ratio in Usher type I carriers compared to normal control individuals. The methods used in this study were found not to be specific enough to clinically identify carriers of Usher type I syndrome. Nevertheless it is remarkable that a number of obligate carriers showed significant audiological and ophthalmological abnormalities. © 1995 Wiley-Liss, Inc.     

郑州地区666例智力障碍儿童异常染色体核型分析

目的探讨666例智力障碍儿童异常染色体的核型分析。方法常规外周血淋巴细胞染色体检查。结果与结论1014例中共发现染色体正常（320—550条带阶段未见染色体异常）的350例,染色体异常666例,占全部受检病例的65．7％（666／1014）,其中各种类型的21三体综合征（Down’s）644例,占染色体异常核型的96．7％（644／666）,其中有1例47,XY,＋21,t（2;5）为世界首报核型。其余异常核型分别涉及到2、3、5、7、8、9、10、12、13、14、15、16、18、22号染色体共20例。表明引起儿童智力障碍染色体异常是重要原因,而Down’s综合征又是染色体异常中最主要的原因．达96．7％。     

Incidence of major chromosomal abnormalities in a referred population for suspected chromosomal aberrations: a report of 357 cases

The present report describes the cytogenetic findings in 357 cases referred for suspected chromosomal abnormalities because of abnormal clinical features. Chromosomal anomalies were found in 97 (27.2 %) of the cases studied. A significantly high rate of chromosomal abnormalities was found in a population with clinical abnormalities in comparison to an unselected population (0.48–0.55 %).     

Structural abnormalities and persistent complaints after an ankle sprain are not associated: an observational case control study in primary care

Background

Persistent complaints are very common after a lateral ankle sprain.

Aim

To investigate possible associations between structural abnormalities on radiography and MRI, and persistent complaints after a lateral ankle sprain.

Design and setting

Observational case control study on primary care patients in general practice.

Method

Patients were selected who had visited their GP with an ankle sprain 6–12 months before the study; all received a standardised questionnaire, underwent a physical examination, and radiography and MRI of the ankle. Patients with and without persistent complaints were compared regarding structural abnormalities found on radiography and MRI; analyses were adjusted for age, sex, and body mass index.

Results

Of the 206 included patients, 98 had persistent complaints and 108 did not. No significant differences were found in structural abnormalities between patients with and without persistent complaints. In both groups, however, many structural abnormalities were found on radiography in the talocrural joint (47.2% osteophytes and 45.1% osteoarthritis) and the talonavicular joint (36.5% sclerosis). On MRI, a high prevalence was found of bone oedema (33.8%) and osteophytes (39.5) in the talocrural joint; osteophytes (54.4%), sclerosis (47.2%), and osteoarthritis (55.4%, Kellgren and Lawrence grade >1) in the talonavicular joint, as well as ligament damage (16.4%) in the anterior talofibular ligament.

Conclusion

The prevalence of structural abnormalities is high on radiography and MRI in patients presenting in general practice with a previous ankle sprain. There is no difference in structural abnormalities, however, between patients with and without persistent complaints. Using imaging only will not lead to diagnosis of the explicit reason for the persistent complaint.     

Kabuki syndrome: description of dental findings in 8 patients

The cardinal features of Kabuki (Niikawa-Kuroki) syndrome (KS) include characteristic facial dysmorphic features, mild to moderate mental deficiency, skeletal abnormalities, dermatoglyphic abnormalities, and postnatal growth retardation. We identified 8 patients with KS in a genetics clinic over the past 5 years. All were Caucasians, except for 2 who were of mixed Aboriginal and Caucasian descent. All had the facial gestalt, the dermatoglyphic abnormalities characteristic of the syndrome, and developmental delay. Dental abnormalities of permanent teeth were seen in all 8 cases; 6 had missing lower incisors. Five patients had uniquely abnormal upper incisor teeth shape; the upper incisors had a 'flat head' screwdriver-shaped appearance. Other dental abnormalities included missing lower lateral incisors, missing second premolars, and ectopic upper 6-year molars. We believe the presence of the unique dental findings will prove useful in the diagnostic assessment of individuals with KS.     

发育异常患者90例染色体核型分析

目的探讨染色体核型异常与发育异常的关系。方法对2004年5月到2008年5月到吉林省生殖医学研究所临床基地进行遗传咨询的2485例患者进行外周血淋巴细胞培养,染色体核型分析。结果2485例遗传咨询者中,染色体核型异常257例,异常率为10.34%。在染色体异常核型中,性染色体异常154例,占59.92%;常染色体异常103例,占40.08%。其中发育异常患者90例,占35.02%。结论发育异常与染色体核型异常有着密切的关系,对发育异常患者进行染色体核型分析,有利于临床诊断,也可为遗传咨询提供依据。     

Usher syndrome: results of a screening program in Colombia

Otological, ophthalmological and genetic studies were performed in 46 patients with Usher syndrome, identified through a screening program in Colombia. Of them, 69.6% had Usher syndrome type I, 26.1% type II, and 4.3% type III. Thirty-three patients showed profound deafness (71.7%), while 13 (28.3%) had moderate to severe hearing loss. The ophthalmologic manifestations showed marked variability. Although the majority of the patients had serious ocular impairment before age 20. 32.6% had good central visual acuity. The prevalence of Usher syndrome in Colombia, estimated at 3.2/100000, warrants the implementation of screening programs in schools for the deaf and for the blind. Our study confirms that Usher syndrome shows no geographic or racial variation and that the disorder has a wide variability of expression and genetic heterogeneity. The large size of the families we have detected may provide important opportunities for further genetic studies, particularly in terms of the assignment of the locus and gene mapping.     

36例X染色体异常的遗传学分析

目的通过对36例女性性发育异常患者的核型分析,进一步探讨X染色体异常的遗传学效应。方法采用外周血淋巴细胞培养制片、染色体G显带技术进行核型分析。结果36例性发育异常患者中X染色体数目异常26例,结构异常10例。结论女性X染色体异常可导致性腺发育不全,身材矮小,原发闭经,月经紊乱等,两条完整的X染色体对女性性腺及体征的发育是十分重要的。     

Cytogenetic profile of patients with clinical spectrum of ambiguous genitalia,amenorrhea, and Turner phenotype: A 21‐year single‐center experience

The aim of the present study was to determine the frequency and nature of chromosomal abnormalities involved in patients with the clinical spectrum of ambiguous genitalia (AG), amenorrhea, and Turner phenotype, in order to compare them with those reported elsewhere. The study was conducted in the Cytogenetic Department of Pasteur Institute of Morocco, and it reports on the patients who were recruited between 1996 and 2016. Cytogenetic analysis was performed according to the standard method. Among 1,415 patients, chromosomal abnormalities were identified in 7.13% (48/673) of patients with AG, 17.39% (28/161) of patients with primary amenorrhea (PA), 4% (1/25) of patients with secondary amenorrhea, and 23.20% (129/556) of patients with Turner phenotype. However, Turner syndrome was diagnosed in 0.89% (6/673) of patients with AG, 10.56% (17/161) of patients with PA, and 19.78% (110/556) of patients with Turner phenotype. In addition, Klinefelter syndrome and mixed gonadal dysgenesis were confirmed in 2.97% and 1.93% of patients, respectively, with AG, while, chimerism, trisomy 8, and trisomy 13 were confirmed only in 0.15% each. Trisomy 21 was confirmed in patients with AG and Turner phenotype (0.15% and 0.36%, respectively). Moreover, 5.60% (9/161) of patients with PA have been diagnosed as having sex reversal. Thus, the frequency of chromosomal abnormalities observed in Moroccan patients with PA is comparable to that reported in Tunisia, Turkey, Iran, and Hong Kong. However, the frequency is significantly less than that identified in India, Malaysia, Italy, and Romania.     

攀枝花地区400例不良孕产史遗传咨询者细胞遗传学分析

目的对攀枝花地区400例不良孕产史患者行外周血染色体检查,分析攀枝花地区不良孕产史与患者外周血染色体异常的关系。方法按照便利抽样法选取2016年1月~2018月12月在我院诊治的不良孕产史遗传咨询者400例作为研究对象,抽取患者的外周血进行淋巴细胞培养,行染色体制片,采用常规G显带技术对染色体的核型进行分析。结果 400例不良孕产史患者共检出21例染色体异常核型,检出率为5.25%。其中,56例自然流产1次检出异常核型2例,检出率为0.5%;169例自然流产2次检出异常核型5例,检出率为1.25%;67例自然流产3次及以上检出异常核型8例,检出率为2%;32例生育畸形胎儿史检出异常核型1例,检出率为0.25%;46例男性不育检出异常核型3例,检出率为0.75%;30例女性原发不孕检出异常核型2例,检出率为0.5%。染色体异常核型中,4例相互易位,检出率为1%;1例罗伯逊易位,检出率为0.25%;16例多态改变,检出率为4%。自然流产1次、自然流产2次、自然流产3次及以上三组组间比较,差异有统计学意义(P<0.05)。结论染色体异常核型是导致患者发生不良孕产史的主要因素,因此对有不良孕产史的患者进行染色体核型分析,有利于临床医生对患者的病因进行诊断,为不良孕产进行治疗,减少畸形胎儿的出生率,对观测落实优生优育具有重要临床指导价值。     

胎儿结构畸形、微小畸形与染色体异常的相关性研究

目的通过对不同类型和数量的胎儿结构畸形、微小畸形与染色体异常的关系性研究,从而对具有上述病变的胎儿的遗传咨询和染色体产前诊断做一个更好的指引。方法收集2004年1月至2005年12月因发现胎儿结构畸形和微小畸形于孕中晚期进行脐带穿刺术及染色体检查病例120例。统计不同的结构畸形、微小畸形的染色体异常核型的检出率、检出类型。并对所有病例进行术后或出生后随访。结果脐带穿刺术和脐血染色体培养成功率为100%,检出异常核型13例(10.8%)。其中18三体异常核型6例,21三体2例,13三体1例,45,XO(Turner综合征)1例,衍生染色体2例,嵌合体1例。多发畸形染色体异常发生率为40%(8/20);单发畸形染色体异常发生率为7.3%(3/41);单独存在的胎儿超声软指标染色体异常发生率为2.1%(1/47);多个超声软指标染色体异常发生率为8.3%(1/12)。结论胎儿结构畸形与非整倍体染色体病关系密切,而单独存在的超声软指标发生染色体异常的机率较低,但当出现2个以上软指标时发生染色体异常的几率将增加。我们应根据结构异常的种类和数量,给予孕妇不同的产前咨询意见和提供必要的侵入性检查。