MedGen

Hereditary myopathy with lactic acidosis (HML) is an autosomal recessive muscular disorder characterized by childhood onset of exercise intolerance with muscle tenderness, cramping, dyspnea, and palpitations. Biochemical features include lactic acidosis and, rarely, rhabdomyolysis. It is a chronic disorder with remission and exacerbation of the muscle phenotype (summary by Sanaker et al., 2010). [from OMIM]

Multifocal atrial tachycardia is a rare supraventricular arrhythmia in neonates and young infants that is characterized by multiple P waves with varying P wave morphology and is usually asymptomatic. [from HPO]