Kallmann syndrome; hypogonadotropic hypogonadism & anosmia
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Epidemiology
- occurs in males
- often familial
Pathology
- absence of GnRH-producing cells in the hypothalamus
- developmental abnormality of the olfactory placode
- GnRH cells that arise in the olfactory placode fail to migrate to the hypothalamus
- impaired axonal extension of olfactory neurons towards the forebrain
- absence or hypoplasia of the olfactory bulbs & tracts
- in some cases, midline cranial anomalies (cleft lip/palate & imperfect fusion) are present & anosmia may be absent or inconspicuous
- renal agenesis, selective tooth agenesis, & bimanual synkinesis in some cases (not type 3)
Genetics
- associated with defects in KAL1 gene (type 1)[1]
- associated with defects in FGFR1 (type 2)[2]
- associated with defects in PROKR2 (type 3)[3]
- associated with defects in PROK2 (type 4)[4]
- associated with defects in CHD7 (type 5)[5]
- associated with defects in FGF8 (type 6)[6]
Clinical manifestations
- sexual infantilism
- testes are prepubertal
- anosmia or hyposmia (80%)
- midline defects that may be present
Laboratory
- decreased serum LH & FSH
- other pituitary hormones are normal
- decreased serum testosterone
Radiology
- magnetic resonance imaging (MRI) of the head is normal
Management
- androgen replacement
- GnRH or gonadotropin therapy
More general terms
Additional terms
- anosmia
- Anosmin-1; kallmann syndrome protein; Adhesion molecule-like X-linked (KAL1, ADMLX, KAL, KALIG1)
References
- ↑ 1.0 1.1 OMIM https://mirror.omim.org/entry/308700
- ↑ 2.0 2.1 OMIM https://mirror.omim.org/entry/147950
- ↑ 3.0 3.1 OMIM https://mirror.omim.org/entry/244200
- ↑ 4.0 4.1 OMIM https://mirror.omim.org/entry/610628
- ↑ 5.0 5.1 OMIM https://mirror.omim.org/entry/612370
- ↑ 6.0 6.1 OMIM https://mirror.omim.org/entry/612702
- ↑ OMIM https://mirror.omim.org/entry/308750
- ↑ Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 235, 274, 278