Clinical and genetic study on a family with metatropic dysplasia due to transient receptor potential vanilloid 4 gene mutation

Abstract

Objective To summarize the clinical, radiographic and genetic features of a family with metatropic dysplasia, in order to improve the level of understanding and diagnosis of this disease. Methods The proband, a one-year old boy, was diagnosed as metatropic dysplasia.His mother was 26 years old with mildly phenotype.Their clinical features and bone X-ray findings were analyzed.The DNA samples of the proband and his parents were collected.The coding exons and flanking introns regions of transient receptor potential vanilloid 4 (TRPV4) gene were amplified by polymerase chain reaction(PCR) and analyzed by DNA automatic detector.The pathology, diagnosis, treatment and prognosis were expounded. Results The symptoms of the boy were characterized by short extremities, a short trunk with progressive kyphoscoliosis, and craniofacial abnormalities that include a prominent forehead, midface hypoplasia, and a squared-off jaw.His motor development was slightly delayed.Mental development was normal.Bone X ray of the boy showed platyspondyly and severe metaphyseal enlargement with shortening of long bones and irregularities and delayed ossification of epiphysis.The patient and his mother were heterozygous for the nucleotide substitutions c. 2396>T (p.P799L) in TRPV4 gene. Conclusions The patient and his mother with metatropic dysplasia were diagnosed with TRPV4 gene analysis.The patient showed typical clinical features.His mother was mild.Metatropic dysplasia had signi-ficantly clinical heterogeneity.Gene analysis is helpful for the diagnosis. Key words: Spondyloepiphyseal dysplasia; Metatropic dysplasia; Transient receptor potential vanilloid 4 channel protein; Transient receptor potential vanilloid 4 gene mutation