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Given below are statements about Kallmann syndrome:

A. It is a condition of hypogonadotropic hypogonadism.
B. There is a loss of sense of smell in such individuals.
C. This syndrome is most common in women.
D. It happens due to mutation of the KALIG1 gene on the X chromosome that codes for an adhesion molecule necessary for the normal development of the gustatory nerve.

Which one of the following options has the combination of all correct statements?

Correct option is D

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Explanation:

1. Statement A - Correct
• Kallmann syndrome is a disorder characterized by hypogonadotropic hypogonadism, meaning the gonadotropin-releasing hormone (GnRH) is deficient, leading to delayed or absent puberty.
2. Statement B - Correct
• Individuals with Kallmann syndrome exhibit anosmia (loss of sense of smell) due to olfactory bulb agenesis or malformation.
3. Statement C - Incorrect
• Kallmann syndrome is more common in men than in women.
• The X-linked inheritance pattern explains why males (who have only one X chromosome) are more frequently affected.
4. Statement D - Incorrect
• Kallmann syndrome is associated with mutations in the KAL1 (Anosmin-1) gene, not the KALIG1 gene.
• It affects the olfactory nerve, not the gustatory (taste) nerve.

Information Booster:

• Kallmann syndrome results from a deficiency of gonadotropin-releasing hormone (GnRH), leading to impaired sexual development.
• The syndrome is associated with defects in neuronal migration, particularly affecting the olfactory bulbs and GnRH-producing neurons.

·       Mutations in the following genes are responsible for Kallmann syndrome:

·       KAL1 (ANOS1) gene (X-linked recessive form)

·       FGFR1, FGF8, PROKR2, PROK2 genes (Autosomal dominant/recessive forms)

·       X-linked inheritance (KAL1 mutation) is most common, which is why males are more frequently affected than females.

·       These mutations affect the migration of olfactory neurons and GnRH-producing neurons, leading to the characteristic symptoms.