PLS3 mutations have recently been identified in about 4% of male individuals with the clinical diagnosis of osteogenesis imperfecta type I or juvenile idiopathic osteoporosis AND normal sequence analysis of the type I procollagen genes (COL1A1 and COL1A2). Most of the known mutations (van Dijk et al. 2013, Fahiminiya et al. 2014, CDL unpublished data) create premature termination codons and, probably, mRNA instability that results in absence of the PLS3 protein. Women who were reported to be PLS3 mutation carriers did not have a history of fractures. PLS3 encodes plastin 3, which is an actin-bundling protein that is highly expressed in the mechanosensing dendrites of osteocyte. Mechanosensing appears to be critical for the conversion of mechanical to intracellular biochemical signals so that the bone architecture can adapt to the constantly changing mechanical demands.
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.
BLOOD IS PREFERRED.
BLOOD: 2 EDTA (purple top) tubes
Whole blood may be stored up to 5-7 days in the refrigerator before shipping.
5 µg DNA at a minimum concentration of ≥200 ng/µl
Oragene Saliva samples are accepted
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 & Cost81479