MedGen

MPV17-related mitochondrial DNA (mtDNA) maintenance defect presents in the vast majority of affected individuals as an early-onset encephalohepatopathic (hepatocerebral) disease that is typically associated with mtDNA depletion, particularly in the liver. A later-onset neuromyopathic disease characterized by myopathy and neuropathy, and associated with multiple mtDNA deletions in muscle, has also rarely been described. MPV17-related mtDNA maintenance defect, encephalohepatopathic form is characterized by: Hepatic manifestations (liver dysfunction that typically progresses to liver failure, cholestasis, hepatomegaly, and steatosis); Neurologic involvement (developmental delay, hypotonia, microcephaly, and motor and sensory peripheral neuropathy); Gastrointestinal manifestations (gastrointestinal dysmotility, feeding difficulties, and failure to thrive); and Metabolic derangements (lactic acidosis and hypoglycemia). Less frequent manifestations include renal tubulopathy, nephrocalcinosis, and hypoparathyroidism. Progressive liver disease often leads to death in infancy or early childhood. Hepatocellular carcinoma has been reported. [from GeneReviews]

A pure form of hereditary spastic paraplegia with characteristics of adult onset of crural spastic paraparesis, hyperreflexia, extensor plantar responses, proximal muscle weakness, mild muscle atrophy, decreased vibration sensation at ankles and mild urinary dysfunction. Foot deformities have been reported to eventually occur in some patients. No abnormalities are noted on brain magnetic resonance imaging and peripheral nerve conduction velocity studies. [from SNOMEDCT_US]

ReNU syndrome (RENU), also known as neurodevelopmental disorder with hypotonia, brain anomalies, distinctive facies, and absent language (NEDHAFA), is characterized by hypotonia, global developmental delay, severely impaired intellectual development with poor or absent speech, delayed walking or inability to walk, feeding difficulties with poor overall growth, seizures (in most), dysmorphic facial features, and brain anomalies, including ventriculomegaly, thin corpus callosum, and progressive white matter loss (Greene et al., 2024; Schot et al., 2024; Chen et al., 2024). [from OMIM]