Autosomal recessive spastic ataxia of Charlevoix–Saguenay : Two case reports

Introduction - Autosomal recessive spastic ataxia of Charlevoix–Saguenay (ARSACS) is a rare neurodegenerative disorder caused by biallelic mutations in the SACS gene. It is classically characterized by the triad of ataxia, pyramidal involvement and axonal-demyelinating sensorimotor neuropathy. We present 2 cases of ARSACS. Case 1 - A 7-years-old girl born of non- consanguineous marriage, presented with mild motor delay, unclear speech and some imbalance in walking since early childhood. However, no significant progression was noted over time. On examination, she had positive cerebellar signs, lower limbs spasticity and hyperreflexia with bilateral pes cavus. MRI brain revealed linear T2-hypointensities in pons, with mild atrophy of superior vermis, cerebellar hemispheres & upper cervical cord (figure-1). Nerve conduction studies showed sensory-motor demyelinating neuropathy. Genetic studies revealed compound heterozygous autosomal recessive mutations in the SACS gene. On 1 year follow up, no progression was noted. Case 2- A 9-years-old boy born of 3rd degree consanguineous marriage, who was recently diagnosed with leukemia & was admitted for the same. History revealed a motor delay with difficulty in walking & performing fine motor activities. Cerebellar signs were positive. Tone & reflexes were normal. MRI showed bulky pons with linear hypointensities & vermian atrophy (figure-2). NCV was normal. Genetic study revealed autosomal recessive mutations in the SACS gene. On 6 months follow up, no neurological progression was noted. Conclusion - ARSACS is a rare disorder, to be kept in mind in early onset slowly progressive spastic ataxia with typical MRI picture of linear pontine hyperintensities.