A Case of MECP2 Duplication Syndrome with Gonadotropin-Dependent Precocious Puberty

MECP2 duplication syndrome, which is caused by duplication of part of the Xq28 region containing the MECP2 gene, causes intellectual disability and mild dysmorphic features in males. To date, precocious puberty has not been reported as a clinical feature of MECP2 duplication syndrome.

A 6-year-old male with severe intellectual disability was referred because of growth acceleration and precocious puberty. We checked his hormonal profile and conducted imaging studies and an array comparative genomic hybridization analysis.

His bone age (9 years and 6 months) was accelerated, and the basal level of testosterone was 8.99 ng/ml. In a luteinizing hormone (LH)-releasing hormone (LHRH) stimulation test, LH increased from 3.69 to 9.32 IU/l, and follicle-stimulating hormone increased from 0.65 to 0.90 IU/l. Chest and abdominal CTs and a brain MRI did not reveal any abnormalities. Treatment with an LHRH analogue effectively suppressed the level of testosterone to <0.03 ng/ml, consistent with the diagnosis of gonadotropin-dependent precocious puberty (GDPP). We identified a duplication of the Xq28 locus including MECP2 in the patient.

Precocious puberty is often a benign central process in girls, but it is rarely idiopathic in boys. The present case raises the possibility that GDPP is a novel clinical feature of MECP2 duplication syndrome.