MedGen

Progressive damage to mitochondrial DNA (mtDNA) during life is thought to contribute to aging processes. This notion is supported by the observation of an aging-related accumulation in human mtDNA of oxidative and alkylation derivatives of nucleotides, of small deletions and insertions, and of large deletions, although their low frequency raises questions about their functional significance (Michikawa et al., 1999). [from OMIM]

Pompe disease is classified by age of onset, organ involvement, severity, and rate of progression. Infantile-onset Pompe disease (IOPD; individuals with onset before age 12 months with cardiomyopathy) may be apparent in utero but more typically onset is at the median age of four months with hypotonia, generalized muscle weakness, feeding difficulties, failure to thrive, respiratory distress, and hypertrophic cardiomyopathy. Without treatment by enzyme replacement therapy (ERT), IOPD commonly results in death by age two years from progressive left ventricular outflow obstruction and respiratory insufficiency. Late-onset Pompe disease (LOPD; including: (a) individuals with onset before age 12 months without cardiomyopathy; and (b) all individuals with onset after age 12 months) is characterized by proximal muscle weakness and respiratory insufficiency; clinically significant cardiac involvement is uncommon. [from GeneReviews]