Idiopathic and genetic forms of multiple pituitary hormone deficiencies Miscellaneous disorders Prader-Willi syndrome Laurence-Moon-Bardet-Biedl syndrome Functional gonadotropin deficiency Chronic systemic disease and malnutrition Hypothyroidism Cushing disease Diabetes mellitus Hyperprolactinemia Anorexia nervosa Psychogenic amenorrhea Impaired puberty and delayed menarche in female athletes and ballet dancers (exercise amenorrhea) Hypergonadotropic hypogonadism Klinefelter syndrome (syndrome of seminiferous tubular dysgenesis) and its variants Other forms of primary testicular failure Anorchia and cryptorchidism Syndrome of gonadal dysgenesis and its variants (Turner syndrome) Other forms of primary ovarian failure XX and XY gonadal dysgenesis Familial and sporadic XX gonadal dysgenesis and its variants Familial and sporadic XY gonadal dysgenesis and its variants Noonan syndrome Galactosemia
Modified from Grumbach MM, Styne DM: Puberty. In Wilson JD, Foster DW, editors: Williams Textbook of Endocrinology, ed 9, Philadelphia, 1998, WB Saunders.
CNS, Central nervous system.
Disorders that can cause hypogonadism include congenital hypopituitarism, such as midline defects, tumors, infiltrative disease (hemochromatosis), and many syndromes, including Laurence-Moon-Bardet-Biedl, Prader-Willi, and Kallmann syndromes. If there is an inability to release gonadotropins but no other pituitary abnormality, the patient has isolated gonadotropin deficiency (almost universally a result of absent GnRH). Patients grow normally until the time of the pubertal growth spurt, when they fail to experience the accelerated growth characteristic of the normal growth spurt.
Kallmann syndrome combines isolated gonadotropin deficiency with disorders of olfaction. There is genetic heterogeneity; some patients have a decreased sense of smell, othershave abnormal reproduction, and some have both. Most casesare sporadic but a number of patients may have mutations inthe KAL1 gene at Xp 22.3 (X chromosome) or KAL2 gene. The mutation causes the GnRH neurons to remain ineffectuallylocated in the primitive nasal area, rather than migrating to thecorrect location at the medial basal hypothalamus. Olfactorybulbs and olfactory sulci are often absent on magnetic resonance imaging (MRI). Other symptoms include disorders ofthe hand, with one hand copying the movements of the otherhand, shortened fourth metacarpal bone, and an absent kidney.
Abnormalities of the Central Nervous System
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Central nervous system (CNS) tumors, including pituitary adenoma, glioma, prolactinoma, or craniopharyngioma, are important causes of gonadotropin deficiency. Craniopharyngiomas havea peak incidence in the teenage years and may cause any type ofanterior or posterior hormone deficiency. Craniopharyngiomasusually calcify, eroding the sella turcica when they expand. Theymay impinge on the optic chiasm, leading to bitemporal hemianopsia and optic atrophy. Other tumors that may affect pubertaldevelopment include astrocytomas and gliomas.
Idiopathic hypopituitarism is the congenital absence of various combinations of pituitary hormones. Although this disorder may occur in family constellations, in X-linked or autosomal recessive patterns, sporadic types of congenital idiopathic hypopituitarism are more common. Congenital hypopituitarism may manifest in a male with GH deficiency and associated gonadotropin deficiency with a microphallus or with hypoglycemia with seizures, especially if adrenocorticotropic hormone and GH deficiency occurs as well.