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. The disease is HSD10 disease, infantile type (MONDO_0018322, a Monarch Disease Ontology entry). Also known as: 2-methyl-3-hydroxybutyric aciduria, classic type, 2-methyl-3-hydroxybutyric aciduria, infantile type, 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency, classic type, 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency, infantile type, HSD10 deficiency, classic type, HSD10 deficiency, infantile type, HSD10 disease, classic type, MHBD deficiency, classic type.