title: Mutations in the gene encoding the calcium-permeable ion channel TRPV4 produce spondylometaphyseal dysplasia, Kozlowski type and metatropic dysplasia.
abstract: The spondylometaphyseal dysplasias (SMDs) are a group of short-stature disorders distinguished by abnormalities in the vertebrae and the metaphyses of the tubular bones. SMD Kozlowski type (SMDK) is a well-defined autosomal-dominant SMD characterized by significant scoliosis and mild metaphyseal abnormalities in the pelvis. The vertebrae exhibit platyspondyly and overfaced pedicles similar to autosomal-dominant brachyolmia, which can result from heterozygosity for activating mutations in the gene encoding TRPV4, a calcium-permeable ion channel. Mutation analysis in six out of six patients with SMDK demonstrated heterozygosity for missense mutations in TRPV4, and one mutation, predicting a R594H substitution, was recurrent in four patients. Similar to autosomal-dominant brachyolmia, the mutations altered basal calcium channel activity in vitro. Metatropic dysplasia is another SMD that has been proposed to have both clinical and genetic heterogeneity. Patients with the nonlethal form of metatropic dysplasia present with a progressive scoliosis, widespread metaphyseal involvement of the appendicular skeleton, and carpal ossification delay. Because of some similar radiographic features between SMDK and metatropic dysplasia, TRPV4 was tested as a disease gene for nonlethal metatropic dysplasia. In two sporadic cases, heterozygosity for de novo missense mutations in TRPV4 was found. The findings demonstrate that mutations in TRPV4 produce a phenotypic spectrum of skeletal dysplasias from the mild autosomal-dominant brachyolmia to SMDK to autosomal-dominant metatropic dysplasia, suggesting that these disorders should be grouped into a new bone dysplasia family.
authors.affiliation: Department of Orthopedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA 90024, USA.
authors.forename: Deborah
authors.initials: D
authors.lastname: Krakow
authors.forename: Joris
authors.initials: J
authors.lastname: Vriens
authors.forename: Natalia
authors.initials: N
authors.lastname: Camacho
authors.forename: Phi
authors.initials: P
authors.lastname: Luong
authors.forename: Hannah
authors.initials: H
authors.lastname: Deixler
authors.forename: Tara L
authors.initials: TL
authors.lastname: Funari
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Bacino
authors.forename: Mira B
authors.initials: MB
authors.lastname: Irons
authors.forename: Ingrid A
authors.initials: IA
authors.lastname: Holm
authors.forename: Laurie
authors.initials: L
authors.lastname: Sadler
authors.forename: Ericka B
authors.initials: EB
authors.lastname: Okenfuss
authors.forename: Annelies
authors.initials: A
authors.lastname: Janssens
authors.forename: Thomas
authors.initials: T
authors.lastname: Voets
authors.forename: David L
authors.initials: DL
authors.lastname: Rimoin
authors.forename: Ralph S
authors.initials: RS
authors.lastname: Lachman
authors.forename: Bernd
authors.initials: B
authors.lastname: Nilius
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Cohn
mesh_terms: D002648:Child; D002675:Child, Preschool; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D020125:Mutation, Missense; D010009:Osteochondrodysplasias / Q000235:genetics*; D050916:TRPV Cation Channels / Q000235:genetics*
chemical_list: D050916:TRPV Cation Channels; C416986:TRPV4 protein, human