title: TRPV4 mutations in children with congenital distal spinal muscular atrophy.
abstract: Inherited disorders characterized by motor neuron loss and muscle weakness are genetically heterogeneous. The recent identification of mutations in the gene encoding transient receptor potential vanilloid 4 (TRPV4) in distal spinal muscular atrophy (dSMA) prompted us to screen for TRPV4 mutations in a small group of children with compatible phenotype. In a girl with dSMA and vocal cord paralysis, we detected a new variant (p.P97R) localized in the cytosolic N-terminus of the TRPV4 protein, upstream of the ankyrin-repeat domain, where the great majority of disease-associated mutations reside. In another child with congenital dSMA, in this case associated with bone abnormalities, we detected a previously reported mutation (p.R232C). Functional analysis of the novel p.P97R mutation in a heterologous system demonstrated a loss-of-function mechanism. Protein localization studies in muscle, skin, and cultured skin fibroblasts from both patients showed normal protein expression. No TRPV4 mutations were detected in four children with dSMA without bone or vocal cord involvement. Adding to the clinical and molecular heterogeneity of TRPV4-associated diseases, our results suggest that molecular testing of the TRPV4 gene is warranted in cases of congenital dSMA with bone abnormalities and vocal cord paralysis.
authors.affiliation: Neuromuscular Unit, IRCCS Stella Maris, Via dei Giacinti 2, 56028 Pisa, Italy. chiara.fiorillo@inpe.unipi.it
authors.forename: Chiara
authors.initials: C
authors.lastname: Fiorillo
authors.forename: Francesca
authors.initials: F
authors.lastname: Moro
authors.forename: Giacomo
authors.initials: G
authors.lastname: Brisca
authors.forename: Guja
authors.initials: G
authors.lastname: Astrea
authors.forename: Claudia
authors.initials: C
authors.lastname: Nesti
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Bálint
authors.forename: Andrea
authors.initials: A
authors.lastname: Olschewski
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Meschini
authors.forename: Christian
authors.initials: C
authors.lastname: Guelly
authors.forename: Michaela
authors.initials: M
authors.lastname: Auer-Grumbach
authors.forename: Roberta
authors.initials: R
authors.lastname: Battini
authors.forename: Marina
authors.initials: M
authors.lastname: Pedemonte
authors.forename: Alessandro
authors.initials: A
authors.lastname: Romano
authors.forename: Valeria
authors.initials: V
authors.lastname: Menchise
authors.forename: Roberta
authors.initials: R
authors.lastname: Biancheri
authors.forename: Filippo M
authors.initials: FM
authors.lastname: Santorelli
authors.forename: Claudio
authors.initials: C
authors.lastname: Bruno
mesh_terms: D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007438:Introns; D008297:Male; D009134:Muscular Atrophy, Spinal / Q000151:congenital / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D050916:TRPV Cation Channels / Q000235:genetics*; D014826:Vocal Cord Paralysis / Q000473:pathology
chemical_list: D050916:TRPV Cation Channels; C416986:TRPV4 protein, human