MEGDEL Syndrome.

MEGDEL syndrome is an autosomal recessive disorder, clinically characterized by 3-methylglutaconic aciduria, psychomotor delay, muscle hypotonia, sensorineural deafness, and Leigh-like lesions on brain magnetic resonance imaging. MEGDEL syndrome is due to mutations in the serine active site-containing protein 1 (SERAC1) gene. The SERAC1 protein is localized at the interface between the mitochondria and the endoplasmic reticulum in the mitochondrion-associated membrane fraction, which is essential for phospholipid exchange. SERAC1 was identified as a key player in phosphatidylglycerol remodeling, which is essential for both mitochondrial function and intracellular cholesterol trafficking. Since the first description of MEGDEL syndrome in 2006, at least 102 patients have been reported. The phenotypic spectrum of MEGDEL syndrome is much broader than so far anticipated. In addition to the brain, ears, and gastrointestinal tract, the eyes, endocrine organs, heart, peripheral nerves, and the skeletal muscle may be affected. Diagnosing MEGDEL syndrome requires a multidisciplinary approach, including genetic confirmation of a SERAC1 mutation. Treatment is supportive, and the outcome is usually poor with early death, except for the juvenile-onset type.