Ataxia-Telangiectasia Masquerading As Cerebral Palsy: A Case Report

Abstract

Ataxia-telangiectasia (A-T) is a rare autosomal recessive multisystem disorder caused by biallelic pathogenic variants in the *ATM* gene. It is characterized by progressive cerebellar ataxia, oculomotor abnormalities, immunodeficiency, telangiectasia, increased susceptibility to malignancy, and progressive neurological dysfunction. Because early neurological manifestations may overlap with cerebral palsy and other developmental disorders, diagnosis can be delayed. Incidence is 1 in 1,00,000 live births.

We report a 3-year-8-month-old girl born to third-degree consanguineous parents who presented with delayed motor development, recurrent falls, progressive gait instability, and right foot deformity. She had initially been evaluated for spastic hemiparesis and possible cerebral palsy. Neurological examination demonstrated generalized hypotonia, bilateral lower-limb spasticity, truncal ataxia, a spastic-ataxic gait, dysmetria, dysdiadochokinesia, slow saccadic eye movements, impaired balance, and dysarthria. Nerve conduction studies demonstrated bilateral peroneal axonal neuropathy, whereas computed tomography of the brain showed no significant structural abnormality. Serum alpha-fetoprotein (AFP) was markedly elevated at 130.4 ng/mL, and serum IgA was reduced to 36 mg/dL, while IgG and IgM were within age-appropriate ranges. Whole-exome sequencing identified a homozygous pathogenic variant in the *ATM* gene involving exons 43–45, confirming the diagnosis of A-T. Additional clinical findings included fewer than three café-au-lait macules and extrapyramidal dyskinesia.

A-T should be considered in children with developmental delay and progressive gait dysfunction, particularly when cerebellar ataxia, slow saccadic eye movements, peripheral neuropathy, or laboratory abnormalities such as elevated AFP are present particularly in a setting of parental consanguinity. Recognition of these clinical clues can prompt appropriate genetic testing and facilitate early multidisciplinary management, surveillance for complications, and genetic counselling.