Laron syndrome E34.3

Laron et al., 1966

Disturbance of motor growth with muscle weakness, pubertas tarda, facial dysmorphia, tooth development disorders, hip dysplasia and hypotrichosis.

Rarely. Worldwide, 200-300 cases have been described, mostly in patients of Semitic ethnicity. Commonly occurring in families with kosanguine compounds.

Autosomal recessive mutations of the GHR gene (growth hormone receptor gene; gene locus: 5p13-p12) and the STAT5B gene (= signal transducer and activator of transcription 5B gene; gene locus: 17q11.2) with defects of the GH receptor. This results in disturbances of the downstream cascade. The GHR gene codes for the " insulin-like growth factor-1 (IGF-1)", which binds to a receptor on the cell surface (IGF-1R). IGF-1R is a regulator of cell proliferation during the development of the hair follicle. The faulty cascade leads to developmental disorders of the hair follicle with consecutive hair shaft abnormalities.

Women and men are affected about equally often.

Highly increased HGH and decreased IGF-1 in the IGF-1 regeneration test. Often hypoglycaemia and hypercholesterolaemia.

Cooperation with pediatricians and endocrinologists. Symptomatic therapy of skin symptoms if necessary. Substitution of IGF-1 is successful in many cases.