RESUMEN

CONTEXT: Gordon Holmes syndrome (GHS) is characterized by cerebellar ataxia/atrophy and normosmic hypogonadotropic hypogonadism (nHH). The underlying pathophysiology of this combined neurodegeneration and nHH remains unknown. OBJECTIVE: We aimed to provide insight into the disease mechanism in GHS. METHODS: We studied a cohort of 6 multiplex families with GHS through autozygosity mapping and whole-exome sequencing. RESULTS: We identified 6 patients from 3 independent families carrying loss-of-function mutations in PNPLA6, which encodes neuropathy target esterase (NTE), a lysophospholipase that maintains intracellular phospholipid homeostasis by converting lysophosphatidylcholine to glycerophosphocholine. Wild-type PNPLA6, but not PNPLA6 bearing these mutations, rescued a well-established Drosophila neurodegenerative phenotype caused by the absence of sws, the fly ortholog of mammalian PNPLA6. Inhibition of NTE activity in the LßT2 gonadotrope cell line diminished LH response to GnRH by reducing GnRH-stimulated LH exocytosis, without affecting GnRH receptor signaling or LHß synthesis. CONCLUSION: These results suggest that NTE-dependent alteration of phospholipid homeostasis in GHS causes both neurodegeneration and impaired LH release from pituitary gonadotropes, leading to nHH.

Asunto(s)

Ataxia Cerebelosa/genética , Hormona Liberadora de Gonadotropina/deficiencia , Hipogonadismo/genética , Degeneración Nerviosa/genética , Fosfolipasas/genética , Pubertad Tardía/genética , Adolescente , Hidrolasas de Éster Carboxílico/genética , Hidrolasas de Éster Carboxílico/metabolismo , Ataxia Cerebelosa/metabolismo , Salud de la Familia , Femenino , Hormona Liberadora de Gonadotropina/genética , Hormona Liberadora de Gonadotropina/metabolismo , Homeostasis/genética , Humanos , Hipogonadismo/metabolismo , Masculino , Persona de Mediana Edad , Degeneración Nerviosa/metabolismo , Linaje , Fosfolipasas/metabolismo , Fosfolípidos/metabolismo , Pubertad Tardía/metabolismo