Laron's syndrome
Contents:
Description:
Laron's syndrome (Laron's dwarfism; Lorain's disease, type II; defect of receptors of STG) — a hereditary disease with an autosomal and recessive mode of inheritance — the peculiar kind of dwarfism (low-tallness) caused by the inborn defect of a gene of a receptor of somatotropic hormone (STG) resulting in nonsensitivity of peripheral fabrics to action of a growth hormone. Resistance to IFR-1 is revealed at the African pygmies.
Reasons of a syndrome of Laron:
Laron's dwarfism is caused by defects of a gene located in cells of a liver of a receptor of STG (growth hormone) or (more rare) defects of a gene of STG — even at the increased growth hormone level in a blood plasma its action on target cells is sharply weakened.
At the healthy person the growth hormone stimulates secretion of the insulinopodobny growth factor (IGF) which in particular stimulates growth of fabrics. At dwarfs the maintenance of IFR is reduced that as it appeared, is the reason, the fact that at people with Laron's syndrome cancer tumors do not develop. The made experiments showed that ruptures of DNA in cells which quite often become the reason of development of tumors at dwarfs occur much less often, and, above all such cells make apoptosis (self-destruction). When added IFR to blood of dwarfs, cells in it became less subject to apoptosis.
People with Laron's syndrome have no diabetes, however the reason of it so far is up to the end not clear.
Average height of men is about 130 cm, women — 120 cm.
Symptoms of a syndrome of Laron:
Patients are born with the normal or reduced length of a body, there is no deficit of weight. With age degree of a growth inhibition accrues, surplus of body weight progresses. The "doll" person, small growth, slight obesity, a high pitched voice create an appearance of the cupid. Sexual development is detained, occurs spontaneously, patients are fertile. The intelligence is kept. Late terms of ossification of a skeleton and teething. Symptom complex: a proportional growth inhibition, the "doll" person, a gipersomatotropinemiya, resistance to STG. Dissociation between the STG high level and low concentration of somatomedins is characteristic. Introduction of a growth hormone does not cause growth stimulation.
Laron's syndrome, family form at sisters of 6 and 4 years.
Treatment of a syndrome of Laron:
Treatment by growth hormone drugs, as a rule, without results. Assume that for treatment it is possible to use IFR-1.
