Whole exome sequencing is an efficient, sensitive and specific method for determining the genetic cause of short-rib thoracic dystrophies.

Short-rib thoracic dystrophies (SRTDs) are congenital disorders due to defects in primary cilium function. SRTDs are recessively inherited with mutations identified in 14 genes to date (comprising 398 exons). Conventional mutation detection (usually by iterative Sanger sequencing) is inefficient and expensive, and often not undertaken. Whole exome massive parallel sequencing has been used to identify new genes for SRTD (WDR34, WDR60 and IFT172); however, the clinical utility of whole exome sequencing (WES) has not been established. WES was performed in 11 individuals with SRTDs. Compound heterozygous or homozygous mutations were identified in six confirmed SRTD genes in 10 individuals (IFT172, DYNC2H1, TTC21B, WDR60, WDR34 and NEK1), giving overall sensitivity of 90.9%. WES data from 993 unaffected individuals sequenced using similar technology showed two individuals with rare (minor allele frequency <0.005) compound heterozygous variants of unknown significance in SRTD genes (specificity >99%). Costs for consumables, laboratory processing and bioinformatic analysis were

Review of perinatal management of arthrogryposis at a large UK teaching hospital serving a multiethnic population.

OBJECTIVE: To review the prevalence and perinatal management of cases of arthrogryposis delivering at our hospital over a 6-year period. METHODS: This was a retrospective review of cases of arthrogryposis managed at a UK teaching hospital. Cases were identified from the regional congenital anomalies register and departmental databases. Case notes were reviewed and analysed. RESULTS: From 2002 to 2007, there were 27 cases of arthrogryposis. Sixteen (59.3%) were Caucasians, 7(25.9%) Asians and 4(14.8%) Afro-Caribbean; 17(63%) were nulliparous. In eight (29.6%) cases, there was a family history of congenital anomalies. Three had previously affected siblings and in three cases the parents were affected with arthrogryposis. Five (18.5%) were from consanguineous families. Eighteen (66.7%) cases were diagnosed prenatally at a mean gestational age of 21 weeks. Twelve (57%) were delivered by caesarean section. There were 18 live births. Sixteen (59%) cases were reviewed by clinical geneticist. Following detailed review and investigation including post-mortems, 20 (74%) of our cases had a formal diagnosis or likely cause identified. CONCLUSIONS: Suspected cases of arthrogryposis require multi-disciplinary management to optimise the possibility of making a diagnosis and providing parents with accurate information to enable them to make informed choices regarding the pregnancy and providing information regarding likelihood of recurrence.

Reduced penetrance alleles for Huntington's disease: a multi-centre direct observational study.

OBJECTIVE: To obtain penetrance data for Huntington's disease when DNA results are in the range of 36-39 CAG repeats and assess the consistency of reporting the upper allele from two reference centres. METHOD: Data were collected anonymously on age of onset or age last known to be unaffected from a cohort of individuals with results in this range. DNA samples were re-analysed in two reference centres. Kaplan-Meier analysis was used to construct an age of onset curve and penetrance figures. RESULTS: Clinical data and concordant DNA results from both reference centres were available for 176 samples; penetrance figures (and 95% confidence intervals) for this cohort, at age 65 and 75 years, were 63.9% (55.5% to 73.2%) and 74.2% (64.2% to 84.2%), respectively. Inclusion of 28 additional subjects for whom repeat DNA results were unavailable, obtained from only one reference centre, or discrepant by one repeat within this range, gave penetrance data (including 95% confidence intervals) at ages 65 and 75 years of 62.4% (54.4% to 70.4%) and 72.7.% (63.3% to 82.1%), respectively. 238 duplicate results were available from the reference centres; 10 (4.2%) differed by one CAG repeat in the reporting of the upper allele and in two (0.84%) of these cases the discrepancy was between 39 and 40 repeats. CONCLUSION: When DNA results are in this range, a conservative approach is to say that there is at least a 40% chance the person will be asymptomatic at age 65 years and at least a 30% chance the person will be asymptomatic at age 75 years.

Genomic duplication in Dyggve Melchior Clausen syndrome, a novel mutation mechanism in an autosomal recessive disorder.

BACKGROUND: Dyggve Melchior Clausen syndrome (DMC) is a severe autosomal recessive skeletal dysplasia associated with mental retardation. Direct sequencing of genomic DNA has identified causative mutations in the gene Dymeclin (chromosome 18q12-21), with the majority predicting the generation of a truncated protein product. OBJECTIVE: To carry out molecular genetic studies in three DMC kindreds. RESULTS: Two novel nonsense mutations and two complex genomic duplication events resulting in exon repetition were identified. CONCLUSIONS: Exon dosage assessment or mRNA analysis, in addition to direct genomic DNA sequencing, should be employed in the investigation of DMC affected individuals. Genomic duplication may be the causative mutation mechanism in other autosomal recessive disorders.

Partially matched related donor peripheral blood progenitor cell transplantation in paediatric patients adding fludarabine and anti-lymphocyte gamma-globulin.

Twenty-one paediatric patients (11 males and 10 females) received a CD34-selected partially matched related donor transplant for malignant (16 cases) and non-malignant conditions (five cases). The average cell dose was 11.13 x 10(6)/kg. Fifteen of 16 patients with malignant conditions and one with non-malignant disease received total body irradiation plus cyclophosphamide. Three of 5 patients with non-malignant conditions and one with leukaemia, received busulphan plus cyclophosphamide. One patient with Fanconi anaemia received 100 mg/kg of cyclophosphamide. Fludarabine (25 mg/m(2)/day for 5 days) was administered prior to all these regimens. Additionally, anti-lymphocyte gamma-globulin (12.5 mg/kg/day) was administered from day -2 to day +2. Three (15%) patients failed to achieve complete chimaerism (CC). These patients received a second cell infusion. Two of them achieved CC. In the third patient, the percentage of donor cells was increased. The likelihood for engraftment was not related to the cell dose received. Acute graft-versus-host disease (GVHD) occurred in nine patients but only one developed GVHD >grade II. Eight patients developed active viral infections, which resolved after treatment. Patients receiving cell doses higher than our average had a significantly faster CD3 and CD4 cell recovery and experienced a lower incidence of viral infections. After 480 +/- 255 days of median follow-up, 16/21 patients are alive and well and have CC. Three patients died of leukaemic relapse and a fourth from progression of his disease (adreno-leuko-dystrophy). We conclude that partially matched related donors are a feasible source of haemopoietic progenitor cells for transplantation for patients without matched familial or unrelated donors.