Compressive Myelopathy Secondary to TRPV4 Skeletal Dysplasia: Spondylometaphyseal Dysplasia, Kozlowski Type

Abstract

Transient receptor potential vanilloid 4 channel (TRPV4) gene mutations have been described in skeletal system and peripheral nervous system pathology. The case described here is a 9-year-old male child patient, born to a nonconsanguineous marriage with normal birth history who had difficulty in walking and stiffness of joints for the last 7 years, and progressive weakness of all four limbs and urine incontinence for 1 year following falls. Physical examination showed below-average weight and height and short trunk. Musculoskeletal examination revealed bony prominence bilaterally in the knee joints and contractures in knee and elbow joints with brachydactyly; muscle tone was increased, with brisk deep tendon reflexes. Skeletal survey showed platyspondyly with anterior beaking with metaphyseal dysplasia. Magnetic resonance imaging of the spine revealed atlantoaxial instability with hyperintense signal changes at a cervicomedullary junction and upper cervical cord with thinning and spinal canal stenosis suggestive of compressive myelopathy with platyspondyly and anterior beaking of the spine at cervical, thoracic and lumbar vertebrae. Exome sequencing revealed a heterozygous de novo variant c.2389G > A in exon 15 of TRPV4, which results in the amino acid substitution p.Glu797Lys in the encoded protein. The characteristics observed indicated spondylometaphyseal dysplasia, Kozlowski type (SMD-K). The child underwent surgical intervention for compressive myelopathy by reduction of atlantoaxial dislocation with C1 lateral mass and C2 pars fusion using rib graft and fixation using screws and rods. To conclude, for any child presenting with progressive kyphoscoliosis, short stature, platyspondyly, and metaphyseal changes, a diagnosis of SMD-K should be considered and the patient and family should be advised to avoid spinal injuries.

Keywords

TRPV4 mutation - spondylometaphyseal dysplasia - Kozlowski type - compressive myelopathy - atlantoaxial dislocation

Authors' Contributions

V.K.G. supervised, guided, and reviewed the article; V.M.S. was involved in management of the child patient and preparation of the article; V.M.R., D.K.V., R.H.R., and S.K.S. were involved in diagnosis of the patient and preparation of the article; G.B.V. was involved in analysis of data, interpretation of the case, and preparation of the article.

Publication History

Received: 20 May 2021

Accepted: 22 November 2021

Article published online:
06 January 2022

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