Riboflavin treatment in 3 cases with ETFDH gene mutation

Classical multiple acyl-CoA dehydrogenase deficiency (MADD) is known to occur secondary to mutations in electron transfer flavoprotein dehydrogenase (ETFDH) gene. A family with ETFDH gene mutation heterozygous in parents, heterozygous in one sibling, normal in one sibling and homozygous in 3 siblings are presented (exon 10 c.1130T>C (p.Leu377Pro) rs387907170). 14-year-old female patient presented with difficulty in walking, dysphagia, muscle weakness and tremor. The first complaints appeared when she was 6 years old. There was history of many hospital admissions. She has four sisters and two brothers. One of her sisters was 7 years old and she was vomiting in every month for 3-4 days. One of her brothers was 5 years old and his complaints started recently. Her complaints progressively increased. Because of progressive proximal limb and truncal muscle weakness she cannot sit or walk without support, and she also has myalgia and dysphagia, generalized muscle weakness, evident weakness on neck, upper extremity muscle strength 4/5, lower extremity muscle strength 3/5. Muscle enzymes were elevated initially (CK >4267 IU/mL, AST 787 IU/mL, ALT 134 IU/mL). EMG showed myopathic changes in the proximal muscles. We started Riboflavin and co-enzyme. Four days later her complaints regressed. In the follow-up, she continued to use her medications and never had any complaint. The three cases reported here indicated that glutaric aciduria type 2 should be included in the differential diagnosis of myopathies and recurrent vomiting in children, and that for differential diagnosis we should perform genetic tests for ETFDH gene mutation.
Keywords: ETFDH mutation, riboflavin-responsive myopathy, multiple acyl-CoA dehydrogenase deficiency