Progressive Cerebellar Atrophy and a Novel Homozygous Pathogenic DNAJCI9 Variant as a Cause of Dilated Cardiomyopathy Ataxia Syndrome

BACKGROUND: The dilated cardiomyopathy with ataxia syndrome is a rare autosomal recessive multisystem disorder caused by mutations in DNAJCI9. We present a new patient with a novel pathogenic variant in DNAJCI9 with novel neuroimaging finding of progressive cerebellar atrophy. PATIENT DESCRIPTION AND RESULTS: We describe a new patient with dilated cardiomyopathy with ataxia syndrome presenting with global developmental delay, hypotonia, ataxia, and dilated cardiomyopathy. During follow-up, her cardiac phenotype improved but she exhibited progressive cerebellar atrophy and developed bilateral increased T2 signal intensities in the thalami, parietal lobes, and pons on magnetic resonance imaging. Dilated cardiomyopathy and 3-methylglutaconic aciduria in her urine organic acid analysis also improved. CONCLUSIONS: This child with dilated cardiomyopathy with ataxia syndrome developed progressive cerebellar atrophy, a novel feature of this syndrome. In individuals with global developmental delay, hypotonia, ataxia, the dilated cardiomyopathy with ataxia syndrome should be considered even in the differential diagnosis in the absence of cardiomyopathy or 3-methylglutaconic aciduria.