Growth, puberty and endocrine function in beta-thalassaemia major.
Although delay in onset of puberty is a common cause of growth failure in adolescent thalassaemic patients, growth retardation could also be due to iron overload, the toxic effects of desferrioxamine, or the development of other endocrinopathies such as GH insufficiency or primary hypothyroidism. Abnormal body proportions with truncal shortening are commonly seen and could be due to the disease itself, iron toxicity, delay in puberty or the toxic effects of desferrioxamine. The absence of a pubertal growth spurt during spontaneous or induced puberty is detrimental to the achievement of a normal final adult height. Low serum IGF-I and normal GH reserve in short thalassaemic children imply that a state of relative GH resistance exists. The rise in IGF-I and improvement in growth with GH therapy suggest that this GH resistance is only partial. Although the results of short-term GH therapy are encouraging, the impact of treatment on final height of non-GH deficient short thalassaemic children remains uncertain. Multiple endocrinopathies, including hypogonadism, hypothyroidism and diabetes mellitus, occur mainly in older patients who tend to have high serum ferritin levels. Prognosis for survival is greatly improved if the serum ferritin is kept below 2000 micrograms/l by regular chelation. Chelation therapy initiated early before the accumulation of a significant iron burden or dosages of desferrioxamine in excess of 50 mg/kg/day should be avoided. Serum ferritin should be checked regularly and the "toxicity index" should be used to monitor chelation therapy. In cases of delayed puberty, sexual development should be induced at an appropriate age.
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Department of Paediatrics, University of Hong Kong, Hong Kong.
D000293:Adolescent; D000328:Adult; D002648:Child; D003676:Deferoxamine / Q000009:adverse effects / Q000627:therapeutic use; D004702:Endocrine Glands / Q000503:physiopathology*; D005260:Female; D006130:Growth Disorders / Q000209:etiology*; D019382:Human Growth Hormone / Q000172:deficiency; D006801:Humans; D007037:Hypothyroidism / Q000209:etiology; D008297:Male; D011628:Puberty, Delayed / Q000209:etiology*; D017086:beta-Thalassemia / Q000150:complications* / Q000503:physiopathology* / Q000628:therapy
D019382:Human Growth Hormone; D003676:Deferoxamine