HSD10 disease, infantile type is a clinical subtype of HSD10 disease, a rare neurometabolic disorder. It is characterized by normal early development until 6-18 months of life, followed by progressive neurodegeneration manifesting with developmental regression, progressive visual and hearing troubles, seizures, epilepsy, severe cardiomyopathy, lethargy, hypotonia, poor feeding, choreoathetosis, and movement disorders. Elevated blood levels of isoleucine metabolites and their excretion in urine are reported. The disease is usually fatal around 2-4 years of age.