Functional characterisation of MeCP2 mutations found in male patients with X linked mental retardation

igh myopia often appears as a familial disease. It is usually defined as a refraction error equal to or below -6 diopters (D) in each eye. 1 Highly myopic patients represent 27-33% of the myopic population. 2 The prevalence of the disease in the general population varies according to the country, from 2.1% in the USA, 2 to 3.2% in France, 3 and up to 9.6% in Spain. 3 High myopia is also termed "pathological" myopia because of its potential complications. The highly myopic eye is usually characterised by an abnormal lengthening and a posterior staphyloma. It is often accompanied by glaucoma, cataracts, macular degeneration, and retinal detachment, leading to blindness when the damage to the retina is extremely severe.