A 19-year-old male presents with absent puberty and anosmia. Laboratory tests show low LH, FSH, and testosterone. The underlying developmental defect in Kallmann syndrome involves failed migration of neurons that produce which hormone?
- A GnRH ✓
- B Oxytocin
- C Dopamine
- D Somatostatin
Correct answer: A. GnRH
Explanation
In Kallmann syndrome, GnRH neurons fail to migrate from the olfactory placode to the hypothalamus during embryogenesis, resulting in hypogonadotropic hypogonadism. The same developmental field defect causes failed olfactory bulb formation, producing anosmia. The genetic defect most commonly involves KAL1 (anosmin-1) or other genes guiding neuronal migration.
Reference: Williams Textbook of Endocrinology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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