Mutations in GDI1 and X-linked non-specific mental retardation.

: Mental retardation (MR) is a complex phenotype characterized by suboptimal functioning of the central nervous system (CNS). It is estimated that from 1 to 3% of the general population is affected with MR. MR or "intellectual disability" can be caused by genetic as well as environmental causes that act on the development and functioning of the CNS prenatally, perinatally or postnatally. Genetic causes of MR include chromosome aneusomies, chromosome structural abnormalities, genomic disorders and monogenic diseases. Amongst children, acute MR (QI 95%), and it can be done quickly. We have found 3 nucleotide (nt) substitutions: an intronic polymorphism at nt 107877 A --> C, a polymorphism in exon 3 at nt 109259 T --> C (Asn73Asn), and an intronic polymorphism at nt 110314 G --> C. The mutations in this gene are common and do not seem to influence the gene expression so as to cause a change in phenotype. These results therefore do not encourage the research of a diagnostic protocol designed for mutational analysis of the GDI1 human gene as the only responsible factor for a complex disease as Mental Retardation X-linked (MRX).