A novel missense pathogenic variants of TMEM53 in an Iranian family with craniotubular dysplasia, Ikegawa type.

Craniotubular dysplasia, Ikegawa type (CTDI) is a rare autosomal recessive skeletal dysplasia characterized by hyperostosis of the calvaria and skull base, metadiaphyseal undermodeling of the long tubular bones, and mild shortening and diaphyseal broadening of the short tubular bones. Its causal gene is TMEM53. Six CTDI families have been reported; however, its clinical course and prognosis still remain to be determined. Here, we report two Iranian siblings carrying a novel homozygous missense variant of TMEM53. The affected individuals were referred for progressive severe visual loss of unknown cause. The patient had severe optic atrophy and optic canal narrowing. Radiographic evaluation suggested the diagnosis of CTDI, which was confirmed by the identification of TMEM53 variant (c.704G > T, p.R235L) co-segregating in the consanguineous family. The proband underwent trans-nasal endoscopic optic canal decompression and showed remarkable improvement in visual acuity and daily visual tasks. We recommend early comprehensive clinical and genetic evaluation followed by proper treatment to improve the prognosis of CTDI.