PEDBASE.org - The Pediatric Database - Detailed information of KALLMANN SYNDROME

KALLMANN SYNDROME

DEFINITION:

An x-linked disorder characterized by a GnRH deficiency with hypogonadotropic hypogonadism and delayed puberty, and smelling deficiencies.

incidence: 1/10,000 (M); 1/50,000 (F)
- 1/25 in hyposmic or anosmic patients
- 1/30 in 46, XY patients with hypogonadism
age of onset:
- adolescence (with delayed puberty)
risk factors:
- familial - x-linked recessive (also autosomal recessive and autosomal dominant forms)
- chrom.#: Xp22.3
- gene: ?
may be associated with other x-linked disorders
- steroid sulfatase deficiency (x-linked ichthyosis)
- Conradi Syndrome
M > F (5:1)

genetic defect -> interference with the migration of GnRH-secreting cells arising from the nasal placode (precursor of the nose) to the hypothalamus during fetal life results in:
- agenesis of the olfactory lobes -> smelling difficulties
- GnRH deficiency -> decreased secretion of LH and FSH -> failure to develop secondary sexual characteristics
GnRH deficiency may be complete or partial
this disorder is considered to be a defect of the hypothalamus and not the pituitary (i.e., secondary hypogonadism)
genetic heterogeneity -> phenotypic heterogeneity

highly variable
- anosmia -> hyposmia -> euosmia
- hypogonadism -> normal gonads
- lack of -> delayed -> normal development of secondary sexual characteristics

renal anomalies (unilateral agenesis)
cryptorchidism in males
- decreased spermatogenesis
- increased risk of testicular tumors

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