Expanding the phenotype and genotype of female GnRH deficiency

Abstract

Context: GnRH deficiency is a rare genetic disorder of absent or partial pubertal development. The clinical and genetic characteristics of GnRH-deficient women have not been well-described.

Objective: To determine the phenotypic and genotypic spectrum of a large series of GnRH-deficient women.

Design, setting, and subjects: Retrospective study of 248 females with GnRH deficiency evaluated at an academic medical center between 1980 and 2010.

Main outcome measures: Clinical presentation, baseline endogenous GnRH secretory activity, and DNA sequence variants in 11 genes associated with GnRH deficiency.

Results: Eighty-eight percent had undergone pubarche, 51% had spontaneous thelarche, and 10% had 1-2 menses. Women with spontaneous thelarche were more likely to demonstrate normal pubarche (P = 0.04). In 27% of women, neuroendocrine studies demonstrated evidence of some endogenous GnRH secretory activity. Thirty-six percent (a large excess relative to controls) harbored a rare sequence variant in a gene associated with GnRH deficiency (87% heterozygous and 13% biallelic), with variants in FGFR1 (15%), GNRHR (6.6%), and PROKR2 (6.6%) being most prevalent. One woman had a biallelic variant in the X-linked gene, KAL1, and nine women had heterozygous variants.

Conclusions: The clinical presentation of female GnRH deficiency varies from primary amenorrhea and absence of any secondary sexual characteristics to spontaneous breast development and occasional menses. In this cohort, rare sequence variants were present in all of the known genes associated with GnRH deficiency, including the novel identification of GnRH-deficient women with KAL1 variants. The pathogenic mechanism through which KAL1 variants disrupt female reproductive development requires further investigation.

Trial registration: ClinicalTrials.gov NCT00392756.

Fig. 1.

A, Representative 12-h pattern of LH secretion in a 25-year-old woman with KS (Subject 17) who harbors two KAL1 RSVs demonstrates an absence of LH pulses. Shaded region represents the normal range for LH in healthy women with normal menstrual cycles in the EFP of their ovulatory menstrual cycles (19, 20). B, Representative 12-h pattern of LH secretion in a 27-year-old woman with nIHH (Subject 5) who carries a TACR3 RSV demonstrates pulses of similar amplitude and frequency to that seen in normal women during the EFP but with amplified pulses during sleep. Shaded region represents the normal range for LH in healthy women with normal ovulatory menstrual cycles in the EFP (19, 20). Arrowheads signify LH pulses, and boxes represent periods of observed sleep.

Fig. 2.

Frequency of rare sequence variants in genes involved in neuronal migration and function of GnRH in KS vs. nIHH women. **, GnRHR variants were more common in nIHH women than in KS women (P < 0.01). Variants in NELF were only identified in KS women, and variants in GNRH1, GPR54, TAC3, and TACR3 were only identified in nIHH women.