GASTROINTESTINAL TRACT INVOLVEMENT ASSOCIATED WITH THE 3243A>G MITOCHONDRIAL DNA MUTATION

Abstract

Defects of the mitochondrial genome (mtDNA) are increasingly recognized as common causes of neurologic syndromes.1 One of the most common pathogenic mtDNA mutations is the m.3243A>G in the MTTL1 gene. In addition to numerous neurologic features this mutation can also give rise to gastrointestinal symptoms including bloating, dysphagia, recurrent vomiting and anorexia, chronic diarrhea, and gastrointestinal pseudo-obstruction.2–4 To gain insight into the pathophysiology of gastrointestinal symptoms associated with the m.3243A>G mtDNA mutation, we investigated the degree of respiratory chain deficiency and the level of m.3243A>G mutation in individual areas from the gastrointestinal tract of two patients in whom gastrointestinal symptoms were both prominent and difficult to manage. ### Case report. Patient 1 developed many features of the mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) syndrome including strokelike episodes, encephalopathy, myopathy, and lactic acidosis. In addition, she had a long history of digestive problems dating back to childhood. She had a small appetite even as a child and felt full even with small portions. During her teenage years constipation became more marked, as well as a feeling of bloating after even a small meal. In later life she developed severe constipation requiring regular enemas and laxatives. She died at age 32 years. Patient 2, who died at age 59 years, was the maternal aunt of Patient 1. She had a …