Introduction

SRD5A3-CDG (MIM 612379) is an extremely rare congenital disease, common manifestations of which are global development delay, intellectual disability, ophthalmological abnormalities (retinitis pigmentosa/retinal dystrophy, optic nerve hypoplasia), cerebellar abnormalities, and hypotonia (1). Only 38 cases of this disease have been reported worldwide, presenting with a highly variable phenotype. While ataxia is mentioned in just under half of these cases, telangiectasia is yet to be reported (2, 3).
Ataxia and telangiectasia are clinical signs that characterize a neurodegenerative disorder known as ataxia-telangiectasia, but can also be seen in other genetic disorders like congenital disorders of glycosylation (CDG) (4). Classically, ataxia-telangiectasia involves multiple organ systems, particularly the nervous and immune systems. From early childhood, those who inherit this autosomal recessive disease develop ataxia: a disability in movement coordination (5). This manifests as problems with walking, balance, and hand coordination, as well as chorea, myoclonus, and neuropathy; a wheelchair is usually needed by adolescence. Patients also suffer from oculomotor apraxia, a condition where looking from one side to the other is difficult. Slurred speech is also prominent. Telangiectasia is one of the two major components of this condition, where enlarged blood vessels are seen in the eyes and skin.
An important note for physicians is that alternative genetic disorders must not be overlooked when a child presents with ataxia and telangiectasia. In this case report, we discuss a seven-year-old boy with a delayed diagnosis of SRD5A3-CDG (MIM 612379; homozygous variant c.57G>A [p.Trp19Ter]), where a diagnosis of ataxia-telangiectasia had been presumed.