Hypochondroplasia

The hypochondroplasia ( HCH) is the most common form of dwarfism dysproportionierten. The disease is autosomal dominant trait and how the achondroplasia caused by mutations in the FGFR3 gene, leading to short stature. The severity of the mutation is lower in the HCH than in achondroplasia.

Frequency

According to estimates HCH occurs in one of 30,000 newborns. The frequency can not be clearly determined because the HCH difficult to distinguish from constitutional short stature.

Cause

The hypochondroplasia is caused by changes of the FGFR3 gene (fibroblast growth factor receptor type 3 gene) on chromosome 4, locus 4p16.3 causes. In this autosomal dominant disease such mutations lead to defects in cartilage formation and thus stunted growth of the extremities.

In 50-60 % of patients, point mutations can be detected. The most common point mutations are C ( 1659) A and C ( 1659) G. Both mutations in the FGFR3 protein in an amino acid exchange at position 540 from asparagine to lysine.

General symptoms of mutation

The symptoms are similar to achondroplasia, but the effects are less. The disproportionated, short-linked short stature is often only hinted at, and the average height is around 140 cm.

Therapy

Sufferers can only be treated symptomatically.