Search
LHRH deficiency (gonadotropin-releasing hormone deficiency)
Epidemiology:
- 1 case per 10,000 men & 1 case per 50,000 women
Pathology:
- loss of the normal pulsatile secretion of LHRH by the pituitary
Genetics:
- defects in PROK2 & its receptor PROKR2 may inhibit migration of hypothalamic neurons secreting LHRH
- defects in GPR54, GnRHR, DAX1, leptin, TAC3, TACR3, NELF, SEMA3A, WDR11, KAL1, FGFR1, FGF8 suggested
Clinical manifestations:
- generally presents when patient fails to begin puberty & does not develop secondary sexual characteristics
- boys may present with micropenis (30%)
- cryptorchidism 50% of boys
- newborn girls have no obvious abnormalities
Laboratory:
- low serum testosterone in males
- low serum LH
- los serum FSH
Radiology:
- magnetic resonance imaging of the inferior frontal region of the brain in the coronal plane is the most useful
Differential diagnosis:
- anosmia suggests Kallmann syndrome
Management:
- androgen replacement in males
- start at age 14-15 years
- oral, injectable, transdermal, & implantable (pellets) androgen formulations currently are available
- in adult males desiring fertility, a different approach to replacement therapy is employed
a) spermatogenesis can be restored with
1] a combination of hCG & human menopausal gonadotropin (FSH & LH]
2] a combintation of hCG & FSH alone
3] GnRH injections
- 25-600 ng/kg every 2 hours delivered subcutaneously using a programmable portable infusion pump
- hormonal contraception in females
- in adult females desiring fertility, a different approach to replacement therapy is employed
- exogenous stimulation of the ovaries is accomplished with various preparations of human menopausal gonadotropin composed of FSH with different concentrations of LH
- intravenous pulsatile GnRH appears to have advantages over gonadotropins
Related
gonadotropin-releasing hormone/factor; gonadoliberin; LH/FSH-releasing hormone (GnRH, LHRH)
Kallmann syndrome; hypogonadotropic hypogonadism & anosmia
General
hypopituitarism
References
- Popat V and Cowan BD
Gonadotropin-Releasing Hormone Deficiency in Adults
http://emedicine.medscape.com/article/255152-overview