Ectodermal dysplasias are a clinically and genetically very heterogeneous group of disorders. In addition to EDA1 and EDAR testing, GeneDx now offers a diagnostic test for WNT10A-related ectodermal dysplasia. Individuals with WNT10A mutations usually have oligodontia, nail dystrophy, dry skin, excessive or reduced sweating and sparse hair. According to recent studies, mutations in the WNT10A gene have been identified in 9% of patients with ectodermal dysplasia and in as many as 25% of individuals who tested negative for a mutation in the EDA1 gene. Once a mutation in WNT10A has been detected in a proband, carrier testing of relatives and prenatal diagnosis are also available.

GeneDx is the first laboratory to offer testing for deletions/duplications in 10 genes associated with Long QT Syndrome (LQTS). It has been shown that approximately 10% of patients with LQTS who test negative for a mutation by DNA sequencing will have a deletion/duplication that involves one of the LQTS genes (Eddy et al. Heart Rhythm 5:1275-1281, 2008). As such deletions/duplications cannot be detected by either NextGeneration or capillary (Sanger) sequencing, GeneDx has developed a high-resolution oligonucleotide microarray for comparative genomic hybridization (array CGH) with probes concentrated in the exons of 10 LQTS genes.

GeneDx now offers full sequencing of four additional genes associated with disorders of sexual differentiation:

GeneDx now offers a cost-effective and sensitive alternative for the diagnosis of the 65 common or novel microdeletion and microduplication syndromes and for examining subtelomeric and pericentromeric genomic regions. This new test, called FISHonChipDx, also includes confirmation of positive findings by FISH. This test has greater technical sensitivity and is more economical than equivalent subtelomere panel and/or single-locus FISH testing. The FISHonChipDx array can also provide size information for detected deletions and duplications. GeneDx also offers individual FISH tests for a range of genomic disorders and for subtelomeric and pericentromeric rearrangements.

GeneDx announces the addition of genetic testing for mutations in the IGHMBP2 gene causing spinal muscular atrophy with respiratory distress type 1 (SMARD1). SMARD1 is characterized by distal muscle weakness and respiratory failure due to diaphragmatic hernia. Genetic testing for IGHMBP2 mutations can help differentiate SMARD1 from other disorders causing muscle weakness and respiratory distress, thereby providing important information to guide medical management. Additionally, prenatal diagnosis and carrier testing of relatives are available once the mutations in a family have been defined.

SDHB, SDHD and SDHC gene analysis in PGL/PCC syndrome

GeneDx is pleased to announce the availability of comprehensive genetic testing for Von Hippel Lindau syndrome. We perform both bi-directional sequencing and deletion/duplication testing by quantitative PCR (CopyDx), thus providing the most comprehensive VHL testing available. The approach used by GeneDx is expected to identify a mutation in almost all individuals with a clinical diagnosis of VHL.