Mitochondrial complex IV deficiency, nuclear type 2

An autosomal recessive, severe mitochondrial disorder characterized by hypotonia, global developmental delay, hypertrophic cardiomyopathy, lactic acidosis, gliosis, and neuronal loss in basal ganglia, brainstem and spinal cord. Serum lactate is increased, and laboratory studies show decreased mitochondrial complex IV protein and activity levels in various tissues, including heart and skeletal muscle. Most patients die in infancy of cardiorespiratory failure.

Mitochondrial complex IV deficiency, nuclear type 4

An autosomal recessive mitochondrial disorder characterized by hypotonia, encephalopathy, metabolic acidosis, poor feeding, hepatomegaly, and hypertrophic cardiomyopathy in some patients. Death occurs in infancy. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV.

Mitochondrial complex IV deficiency, nuclear type 13

An autosomal recessive, infantile disorder with a fatal course in the first weeks of life, characterized by hypertrophic cardiomyopathy, left ventricular non-compaction, lactic acidosis, metabolic hypotonia, and mitochondrial complex IV deficiency.

Mitochondrial complex IV deficiency, nuclear type 9

An autosomal recessive, infantile disorder with a fatal course in the first weeks of life, and characterized by hypertrophic cardiomyopathy and mitochondrial complex IV deficiency. Postmortem microscopic investigations show accumulation of lipid droplets in cardiomyocytes and mitochondrial proliferation.

Mitochondrial complex IV deficiency, nuclear type 6

An autosomal recessive multisystem disorder with variable manifestations. Some patients present in the neonatal period with encephalomyopathic features, whereas others present later in the first year of life with developmental regression. Clinical features include microcephaly, encephalopathy, hypertrophic cardiomyopathy, persistent lactic acidosis, respiratory distress, hypotonia and seizures. Serum lactate is increased, and laboratory studies show decreased mitochondrial complex IV protein and activity levels.