Kallmann's syndrome

The correct answer is C
Explanation

Kallmann's syndrome which is an isolated gonadotropin (LH and FSH) deficiency occurs in both a sporadic and familial form and although uncommon i.e. 1 in 10,000 men, it is second to Klinefelter's syndrome as a cause of hypogonadism. The syndrome is often associated with anosmia, congenital deafness, hair lip, cleft palate, craniofacial asymmetry, renal abnormalities, color blindness. The hypothalamic hormone GnRH appears to be absent.

If exogenous GnRH is administered, both LH and FSH are released from the pituitary. Except for the gonadotropin deficiency, anterior pituitary function is intact. The syndrome appears to be inherited either as an autosomal recessive trait or an autosomal dominant trait with incomplete penetrance.

The differential diagnosis should include delayed puberty. Kallmann's syndrome distinguishing features though are testes less than 2 cm in diameter and positive family history with the presence of anosmia. "Fertile eunuch" are individuals with isolated LH deficiency.

They have eunuchoid proportions with variable degrees of virilization and gynecomastia. They characteristically have large testes and semen containing a few sperm. Plasma FSH levels are normal but both the serum LH and testosterone concentrations are low normal.

The cause appears to be a partial gonadotropin deficiency in which there is adequate LH to stimulate testosterone production with resultant spermatogenesis but insufficient testosterone to promote virilization. In isolated FSH deficiency which is rare, patient's are normally virilized and have normal testicular size and baseline levels of LH and testosterone.

Sperm counts range from O to a few sperm. Serum FSH levels are low and do not respond to GnRH stimulation. Congenital hypogonadotropic syndromes are associated with secondary hypogonadism and a multitude of other somatic findings. Prader-Willi syndrome is characterized by hypogonadism, hypomentia, hypotonia at birth and obesity. Laurence-Moon-Bardet-Biedel syndrome is an autosomal recessive trait characterized by mental retardation, retinitis pigmentosa, polydactyly and hypogonadism. These syndromes are felt to be due to a defect in hypothalamic deficiency of GnRH.

Patients with hypogonadism should be examined with respect to anosmia because such a combination suggests the diagnosis of Kallmann's syndrome. The selection of a therapeutic method should be strictly individual bearing in mind a degree of hypoplasia and the presence of cryptorchism. In the combination of Kallmann's syndrome with cryptorchism CG therapy results in the elimination of cryptorchism without surgery in most patients.

Chorionic gonadotropin should be administered in combination with androgens in marked testicular hypoplasia in any period at the reproductive age; later on it can be only chorionic gonadotropin. Correct diagnosis and adequate therapy lead to sex and social rehabilitation of patients with Kallmann's syndrome decreasing the number of sterile men.

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