| Disease ID | Source | Name | Description |
| 619065 | OMIM | Mitochondrial complex IV deficiency, nuclear type 21 (MC4DN21) | An autosomal recessive mitochondrial disorder with onset in infancy. MC4DN21 is characterized by congenital lactic acidosis, encephalopathy, global developmental delay, delayed speech, motor dysfunction, dystonia, and spasticity. Ataxia, peripheral neuropathy, and seizures may also occur. Patient tissues show variably decreased levels and activity of mitochondrial respiratory complex IV. The disease may be caused by variants affecting the gene represented in this entry. |