Genes
B3GALT6, B3GAT3, B4GALT7, CHST14, CHST3, XYLT1
Test Guide
The Linkeropathies (also called Complex EDS-like disorders) are a group of disorders that result from inherited defects in the synthesis and modification of glycosaminoglycan. The CDL offers a 7 gene panel for autosomal recessive forms of Ehlers-Danlos Syndrome (EDS) that are associated with these defects. Disorders include: progeroid Ehlers-Danlos Syndrome (EDS) (B3GALT6), EDS with short stature and limb anomalies (B4GALT7), musculocontracural-type EDS (CHST14), EDS-like connective tissue disorder (B3GAT3), spondyloepiphyseal dysplasia (CHST3), Desbuquois dysplasia (XYLT1), and spondoocular syndrome (XYLT2). This panel is recommended for individuals with possible autosomal recessive conditions whose clinical features are similar to these disorders.
Methodology
Next Generation Sequencing: Next generation DNA sequencing is performed to identify nucleotide variants in the coding portion of the genome. All nucleotides in the coding exons and their flanking splice junctions are sequenced to a read coverage of greater than 20X. The sequence data are assembled and compared to the published genomic reference sequence. Sanger sequencing is performed if necessary to ensure complete nucleotide coverage of the target sequence and to confirm all reported variants. Human Genome Variation Society (HGVS) recommendations are followed for variant nomenclature and ACMGG/AMP variant interpretation guidelines are followed to assess variant pathogenicity, unless otherwise indicated. The following online databases and in silico analysis tools are routinely used for variant investigation: ClinVar, NHLBI Exome Sequencing Project, 1000 Genomes, dbSNP, Exome Aggregation Consortium (ExAC), available loci specific variant databases, PolyPhen-2, SIFT, Provean, Mutation Taster and Human Splicing Finder.
Specimen Requirements
BLOOD IS PREFERRED.
BLOOD: 2 EDTA (purple top) tubes
Adults: 5-10cc
Children: 3-5cc
Infants: 2-3cc
Whole blood may be stored up to 5-7 days in the refrigerator before shipping.
DNA:
5 µg DNA at a minimum concentration of ≥200 ng/µl
SALIVA:
Oragene Saliva samples are accepted
Special Instructions
Blood samples (or DNA) should be well labeled with patient’s full name and an identifying number.
Ship sample at room temperature with overnight delivery.
Clinical information outlining the indication for the requested tests and pertinent medical history and family history is a necessary component of testing. Please include a clinic note when available.
CPT Code & Cost
81479$1,700.00