Introduction: Infantile neuroaxonal dystrophy (INAD) is a rare infantile onset neurodegenerative disease. Auditory neuropathy was not a reported associated feature of INAD. Investigation of childhood cerebellar atrophy can be challenging. We report our diagnostic approach of a pair of siblings with psychomotor regression, hypotonia, optic atrophy and auditory neuropathy, with progressive cerebellar atrophy. Genetic testing confirmed presence of compound heterozygous novel mutations in PLA2G6.

Case Description: A 22 months-old boy presented with psychomotor regression and progressive muscle weakness. We noticed developmental regression from 17 months. He developed bilateral convergent strabismus, hypotonia, dystonia, tremors, generalized hyper-reflexia, extensor plantar responses, and bilateral optic atrophy. He had normal otoacoustic emissions (OAE) but abnormal auditory brainstem evoked response (ABR) tests, which indicated bilateral profound auditory neuropathy. He later developed swallowing impairment and generalized seizures. Serial brain Magnetic Resonance Imaging (MRI) showed progressive cerebellar atrophy. Extensive metabolic and genetic work-up was negative. Al-Maawali et al’s algorithm on diagnostic approach of childhood-onset cerebellar atrophy was referred to, following which genetic testing for PLA2G6 was performed.  Compound heterozygosity for two novel PLA2G6 mutations were found, confirming the diagnosis of INAD. His younger female sibling also developed similar symptoms at 18 months.

Conclusion: This is the first INAD reported in South East Asia. Our case associated with auditory neuropathy expands the clinical phenotype of INAD. It also reiterates the importance of having a systematic diagnostic approach in the investigation of children with neurodegenerative disease associated with cerebellar atrophy enabling targeted genetic analysis in these children.