Recessive PRDM13 Mutations Result in Hypogonadotropic Hypogonadism and Cerebellar Hypoplasia

PRDM13 (PR Domain containing 13) is a putative chromatin modifier and transcriptional regulator that functions downstream of the transcription factor PTF1A. Here, we report a novel, recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis and delayed puberty with hypogonadotropic hypogonadism (HH). We investigated the development of hypothalamic neurons and the cerebellum in mice homozygous for a Prdm13 mutant allele. Cerebellar hypoplasia was evident, but male gonadal development appeared unaffected in these mutants. As PTF1A has been linked to early GABAergic neuronal cell fate regulation in the spinal cord, we examined GABAergic neuron progenitor development in the hypothalamus and cerebellum. A significant reduction in the number of Kisspeptin neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone was observed. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate during neurodevelopment, providing a mechanistic explanation for the co-occurrence of HH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted regulation of Kiss1 neurons to CHH in humans.