Kannu P.,Murdoch Childrens Research Institute |
Kannu P.,Queens University |
Bateman J.F.,Murdoch Childrens Research Institute |
Randle S.,Glenroy Specialist Center |
And 5 more authors.
Arthritis and Rheumatism | Year: 2010
Mutations in the gene encoding type II collagen (COL2A1) give rise to a spectrum of phenotypes predominantly affecting cartilage and bone. These chondrodysplasias are typically characterized by disproportionately short stature, eye abnormalities, cleft palate, and hearing loss. It is less recognized that mutations in COL2A1 can also present as degenerative joint disease in the absence of any other phenotypic clues. We report 2 Australian families presenting with an isolated arthritis phenotype, segregating as a dominant trait affecting both large and small joints, prior to age 30 years. Sequencing of COL2A1 in the propositi revealed 2 sequence changes resulting in glycine substitutions in the triple-helical domain of type II collagen. We review the increasing evidence implicating COL2A1 mutations in individuals presenting with isolated degenerative joint disease, aiming to alert physicians who assess these patients to this possibility. The importance of finding a COL2A1 mutation in such patients lies in the subsequent ability to accurately assess recurrence risks, offer early (including prenatal) diagnosis, and provide information regarding the natural history of the condition. Most importantly, it enables at-risk individuals to be identified for implementation of preventative strategies (i.e., weight loss, joint-friendly exercise programs) and early ameliorative management of their condition. © 2010, American College of Rheumatology.
Truong H.T.,Charles Sturt University |
Truong H.T.,Virginia Commonwealth University |
Truong H.T.,Keygene NV |
Dudding T.,Hunter Genetics |
And 3 more authors.
BMC Medical Genetics | Year: 2010
Smith-Magenis syndrome (SMS) is a complex syndrome involving intellectual disabilities, sleep disturbance, behavioural problems, and a variety of craniofacial, skeletal, and visceral anomalies. While the majority of SMS cases harbor an ~3.5 Mb common deletion on 17p11.2 that encompasses the retinoic acid induced-1 (RAI1) gene, some patients carry small intragenic deletions or point mutations in RAI1. We present data on two cases of Smith-Magenis syndrome with mutation of RAI1. Both cases are phenotypically consistent with SMS and RAI1 mutation but also have other anomalies not previously reported in SMS, including spontaneous pneumothoraces. These cases also illustrate variability in the SMS phenotype not previously shown for RAI1 mutation cases, including hearing loss, absence of self-abusive behaviours, and mild global delays. Sequencing of RAI1 revealed mutation of the same heptameric C-tract (CCCCCCC) in exon 3 in both cases (c.3103delC one case and and c.3103insC in the other), resulting in frameshift mutations. Of the seven reported frameshift mutations occurring in poly C-tracts in RAI1, four cases (~57%) occur at this heptameric C-tract. Collectively, these results indicate that this heptameric C-tract is a preferential hotspot for single nucleotide insertion/deletions (SNindels) and therefore, should be considered a primary target for analysis in patients suspected for mutations in RAI1. We expect that as more patients are sequenced for mutations in RAI1, the incidence of frameshift mutations in this hotspot will become more evident. © 2010 Truong et al; licensee BioMed Central Ltd.
Huang L.,University of Ottawa |
Chardon J.W.,Childrens Hospital of Eastern Ontario |
Carter M.T.,Hospital for Sick Children |
Friend K.L.,Womens and Childrens Hospital |
And 9 more authors.
Orphanet Journal of Rare Diseases | Year: 2012
Background: Congenital nonprogressive spinocerebellar ataxia is characterized by early gross motor delay, hypotonia, gait ataxia, mild dysarthria and dysmetria. The clinical presentation remains fairly stable and may be associated with cerebellar atrophy. To date, only a few families with autosomal dominant congenital nonprogressive spinocerebellar ataxia have been reported. Linkage to 3pter was demonstrated in one large Australian family and this locus was designated spinocerebellar ataxia type 29. The objective of this study is to describe an unreported Canadian family with autosomal dominant congenital nonprogressive spinocerebellar ataxia and to identify the underlying genetic causes in this family and the original Australian family. Methods and Results. Exome sequencing was performed for the Australian family, resulting in the identification of a heterozygous mutation in the ITPR1 gene. For the Canadian family, genotyping with microsatellite markers and Sanger sequencing of ITPR1 gene were performed; a heterozygous missense mutation in ITPR1 was identified. Conclusions: ITPR1 encodes inositol 1,4,5-trisphosphate receptor, type 1, a ligand-gated ion channel that mediates calcium release from the endoplasmic reticulum. Deletions of ITPR1 are known to cause spinocerebellar ataxia type 15, a distinct and very slowly progressive form of cerebellar ataxia with onset in adulthood. Our study demonstrates for the first time that, in addition to spinocerebellar ataxia type 15, alteration of ITPR1 function can cause a distinct congenital nonprogressive ataxia; highlighting important clinical heterogeneity associated with the ITPR1 gene and a significant role of the ITPR1-related pathway in the development and maintenance of the normal functions of the cerebellum. © 2012 Huang et al.; licensee BioMed Central Ltd.
Hopper B.,Genetic Service |
Buckman M.,Genetic Service |
Edwards M.,Hunter Genetics
Twin Research and Human Genetics | Year: 2011
Telegenetics is a new development in the service delivery of Genetic Services in Australia. This project was designed to establish if it was an acceptable alternative to a face-to-face consultation in the genetic assessment of intellectual disability, including morphological assessment, of the patient. Ten children from two outreach clinics in rural NSW who were referred by their pediatrician were assessed by a single geneticist via telehealth and then seen again face-to-face as a 'gold standard'. Satisfaction surveys were then sent to both the parents and the referring pediatricians. After the face-to-face appointment, the clinical geneticist reviewed the recordings of both the transmitted footage and the high definition footage that was sent separately. There were very few morphological findings missed by the telegenetic assessments. The discrepancies that were noted could decrease in frequency as staff become more familiar with the methods. The parents of the patients reported no problem with the cameras and telehealth. They would have preferred face-to-face appointment but would be happy to have the telehealth appointment if it meant being seen earlier. This pilot study suggests that clinical genetic diagnostic assessment could be performed by telemedicine.
Palmer E.,Sydney Childrens Hospital |
Palmer E.,University of Sydney |
Speirs H.,University of Sydney |
Taylor P.J.,South Eastern Area Laboratory Services SEALS |
And 7 more authors.
American Journal of Medical Genetics, Part A | Year: 2014
Chromosomal microarray (CMA) is the first-line diagnostic test for individuals with intellectual disability, autism, or multiple congenital anomalies, with a 10-20% diagnostic yield. An ongoing challenge for the clinician and laboratory scientist is the interpretation of variants of uncertain significance (VOUS)-usually rare, unreported genetic variants. Laboratories differ in their threshold for reporting VOUS, and clinical practice varies in how this information is conveyed to the family and what follow-up is arranged. Workflows, websites, and databases are constantly being updated to aid the interpretation of VOUS. There is a growing literature reporting new microdeletion and duplication syndromes, susceptibility, and modifier copy number variants (CNVs). Diagnostic methods are also evolving with new array platforms and genome builds. In 2010, high-resolution arrays (Affymetrix 2.7M Oligo and SNP, 50kB resolution) were performed on a community cohort of 67 individuals with intellectual disability of unknown aetiology. Three hundred and one CNVs were detected and analyzed using contemporary resources and a simple scoring system. Thirteen (19%) of the arrays were assessed as potentially pathogenic, 4 (6%) as benign and 50 (75%) of uncertain clinical significance. The CNV data were re-analyzed in 2012 using the contemporary interpretative resources. There was a statistically significant difference in the assessment of individual CNVs (P<0.0001). An additional eight patients were reassessed as having a potentially pathogenic array (n=21, 31%) and several additional susceptibility or modifier CNVs were identified. This study highlights the complexity involved in the interpretation of CMA and uniquely demonstrates how, even on the same array platform, it can be subject to change over time. © 2013 Wiley Periodicals, Inc.