Background. Idiopathic hypogonadotropic hypogonadism (IHH) is manifested as absent or incomplete puberty and biochemically low levels of sex hormones, with low or inappropriately normal gonadotropin hormones. In the absence of structural or functional lesions of the hypothalamic or pituitary gland, the hypogonadism is referred as idiopathic hypogonadotropic hypogonadism (IHH). IHH is a genetically heterogeneous disorder which can be caused by pathogenic variants affecting proteins involved in the pulsatile gonadotropin-releasing hormone release, action, or both.

Case Presentation. A 16-year-old male who presented to the endocrinology clinic with complaints of micropenis and absent secondary sex characteristics. Work up showed an unremarkable cranial MRI, low testosterone, LH, normal FSH, with normal Karyotyping.

Conclusion. Idiopathic hypogonadotropic hypogonadism (IHH) is a rare genetic disease with a complex and still have more to discover about its pathogenesis. The requirements for the diagnosis include low testosterone, low or normal serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations, and a normal appearance of the hypothalamus and pituitary region on magnetic resonance imaging (MRI). A prompt recognition of a clinical hypogonadotrophic hypogonadism is pivotal especially in a peripubertal age to initiate early sex hormone replacement as the failure of secondary sex characteristics could have a derogatory impact on individual’s personal and social life.

Keywords. Hypogonadism, Idiopathic hypogonadotropic hypogonadism (IHH)

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