Caloric restriction in Alström syndrome prevents hyperinsulinemia

Alström syndrome (AS; OMIM 203800) is an autosomal recessive disorder characterized by cone-rod dystrophy, dilated cardiomyopathy, sensorineural hearing impairment, developmental delay, and most case had both childhood-onset obesity and hyperinsulinemia. Currently, the pathogenesis of this disease is not clear. Here we report on an 18-month-old boy with Alström syndrome. He had obesity but with normal insulin and glucose levels. Molecular analysis of the ALMS1 gene revealed a 19 base pair homozygous deletion 11116_11134del in exon 16. His body mass index decreased from 25.0 to 20.7 after calorie restriction for 9 months, and his insulin and glucose levels remained normal. Finding in this case suggests that hyperinsulinemia is a secondary event in Alström syndrome, and early-commenced treatment prevents hyperinsulinemia.