Referenced in: none

Automatically associated channels: TRP , TRPV , TRPV4

Title: TRPV4 related skeletal dysplasias: a phenotypic spectrum highlighted by clinical, radiographic, and molecular studies in 21 new families.

Authors: Elena Andreucci, Salim Aftimos, Melanie Alcausin, Eric Haan, Warwick Hunter, Peter Kannu, Bronwyn Kerr, George McGillivray, R J McKinlay Gardner, Maria G Patricelli, David Sillence, Elizabeth Thompson, Margaret Zacharin, Andreas Zankl, Shireen R Lamande, Ravi Savarirayan

Journal, date & volume: , 2011 Jun 9 , 6, 37

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/21658220

Abstract
The TRPV4 gene encodes a calcium-permeable ion-channel that is widely expressed, responds to many different stimuli and participates in an extraordinarily wide range of physiologic processes. Autosomal dominant brachyolmia, spondylometaphyseal dysplasia Kozlowski type (SMDK) and metatropic dysplasia (MD) are currently considered three distinct skeletal dysplasias with some shared clinical features, including short stature, platyspondyly, and progressive scoliosis. Recently, TRPV4 mutations have been found in patients diagnosed with these skeletal phenotypes.We critically analysed the clinical and radiographic data on 26 subjects from 21 families, all of whom had a clinical diagnosis of one of the conditions described above: 15 with MD; 9 with SMDK; and 2 with brachyolmia. We sequenced TRPV4 and identified 9 different mutations in 22 patients, 4 previously described, and 5 novel. There were 4 mutation-negative cases: one with MD and one with SMDK, both displaying atypical clinical and radiographic features for these diagnoses; and two with brachyolmia, who had isolated spine changes and no metaphyseal involvement.Our data suggest the TRPV4 skeletal dysplasias represent a continuum of severity with areas of phenotypic overlap, even within the same family. We propose that AD brachyolmia lies at the mildest end of this spectrum and, since all cases described with this diagnosis and TRPV4 mutations display metaphyseal changes, we suggest that it is not a distinct entity but represents the mildest phenotypic expression of SMDK.