Central precocious puberty in a boy with 22q13 deletion syndrome and NOTCH-1 gene duplication

The 22q13 deletion syndrome or Phelan-McDermid syndrome is a neurodevelopmental disorder associated with developmental delay, hypotonia, delayed or absent speech, autistic-like behavior, normal to accelerated growth and dysmorphic faces. We report the occurrence of central precocious puberty in a boy diagnosed with Phelan-McDermid syndrome. At the age of 1 year, our patient presented with increased testicular volume for his age, bone age advancement and growth acceleration. Stimulated gonadotropin levels demonstrated a premature activation of the hypothalamic-pituitary-gonadal (HPG) axis. Central precocious puberty was treated with gonadotropin-releasing hormone (GnRH) analog. Molecular diagnosis with array-comparative genomic hybridization (CGH) revealed a major deletion of 5.8 Mb at the 22q13 chromosomal region and a 25 kb duplication at the 9q34.3 region that included the NOTCH-1 gene. On the background of 22q13 deletion syndrome and data from animals on the effect of abnormal NOTCH-1 gene expression on kisspeptin neuron formation, we discuss the probable role of Notch signaling in the premature activation of the HPG axis.