Axial spondylometaphyseal dysplasia associated with biallelic CFAP410 mutations in a 5-year-old girl

Abstract

Axial spondylometaphyseal dysplasia (axial SMD) is an autosomal recessive disorder characterized by dysplasia of the axial skeleton and retinal degeneration. A 5-year-old girl, born of consanguineous parents, presented with thoracic deformities that were first noticed at the age of 1 year. Physical and radiological evaluations showed short stature (−2.7 SD), marked symmetrical deformity of the anterior thorax with a normal sternum, hollowing of the shortened ribs in the mid-parasternal region, flaring of the lower costal margins, and irregular sclerotic lesions at the proximal femoral metaphyses. No other long or short bone metaphyses or epiphyses were affected. On ophthalmological examination, retinal degeneration was seen bilaterally, leading to a clinical diagnosis of axial SMD. DNA analysis of the CFAP410 gene identified biallelic mutations in exon 4 (c.322 C>T, p.Arg108Cys). Understanding the basic processes of bone formation and membranous and endochondral ossification is important for identifying pathognomonic skeletal changes in the radiological diagnosis of skeletal dysplasia.