Pituitary Gigantism
Pituitary gigantism causes abnormal growth in childhood due to excessive secretion of GH. The most common cause is a benign pituitary tumour but the incidence is unknown. In some cases, underlying causes are Carney complex, McCune– Albright syn drome (MAS), multiple endocrine neoplasia type 1 (MEN- 1), and neurofibromatosis. Pituitary gigantism causes bones as well as muscles and internal organs to grow excessively. Other physical features associated include frontal bossing, a prominent jaw, large hands, and feet. It can also cause delayed puberty, headache, muscle weakness, double vision, and sleeping problems. Different treatment methods are available including transsphenoidal surgery, somatostatin analogues, and GH antagonists.
Obesity
Obese children often experience tall stature due to early adrenarche, early puberty, and advanced skeletal maturation. The mechanism is thought to be related to hyperinsulinemia. Insulin binds to the IGF- 1 receptor and increases height velocity. It also increases free IGF- 1 in the circulation. However, adult height is usually not affected due to a more blunted pubertal growth spurt and earlier growth plate closure.
Hyperthyroidism
Thyrotoxicosis in childhood may cause an acceleration of skeletal maturation and linear growth. It is unclear whether this acceleration affects the final height or if it is compensated by an accelerated bone maturation.
Precocious Puberty
Children are considered to experience premature puberty if onset is before 8 years of age for girls and 9 years for boys. Precocious puberty affects approximately one in 500 girls and one in 2000 boys. These girls and boys are tall during childhood, but due to the advancement in skeletal maturation and early growth plate fusion, adult height is usually unaffected or if left untreated sometimes can be reduced.
Familial Glucocorticoid Deficiency
Familial glucocorticoid deficiency (FGD) is characterized by a failure of the adrenal cortex to produce glucocorticoids in spite of normal levels of ACTH. There are different types of this condition caused by different mutations. FGD type 1 is caused by a mutation in the ACTH receptor. Mutations in accessory or regulatory proteins can give the same clinical picture with failure to thrive and hypoglycaemia in early childhood and later an association with tall stature where the mechanism is unclear.
Aromatase Deficiency
Aromatase deficiency is a rare autosomal recessive disease caused by a mutation of the gene CPY19 affecting the aromatization of androgens into oestrogens. This leads to delayed skeletal maturation and open growth plates even after adolescence resulting in extreme tallness unless the patient is treated with oestradiol. Affected girls are born with ambiguous genitalia.
