Molecular study of thePAK3 andGDI1 genes in nonsyndromic X-linked mental retardation Spanish patients

✍ Scribed by Rif�, Maria ;Mallolas, Judith ;Castellv�-Bel, Sergi ;Badenas, C�lia ;Jim�nez, Dolores ;Mil�, Montserrat

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 302 KB
• Volume: 94
• Category: Article
• ISSN: 0148-7299
• DOI: 10.1002/1096-8628(20001023)94:5<389::aid-ajmg9>3.0.co;2-w

✦ Synopsis

Mental retardation (MR) is a common condition with no general mechanism suggested. Mild MR (70 > IQ > 50) is present in 2-3% of the general population, whereas 0.3% presents severe forms of MR (IQ < 50) . Two different forms of MR could be distinguished: nonsyndromic MR, where affected patients do not present any distinctive clinical or biochemical feature in common apart from cognitive impairment, and syndromic MR, where MR is one clinical manifestation of a complex syndrome . Over 15-20% of total X-linked MR corresponds to the fragile X syndrome . Cloning MR-related genes on the X chromosome is simpler than in other autosomal MR forms because males-only pedigrees and their carrier mothers are easily detected . At this time, there are 199 loci described on the X chromosome as syndromic and nonsyndromic MR causes, 125 are mapped and 30 are cloned.

Six new genes responsible for nonsyndromic MR have been described so far, including FMR2 (Xq28), PAK3 (Xq22), GDI1 (Xq28), OPHN1 (Xq12), IL1RAPL (Xp22.1-21.3), and TM4SF2 (Xp11.4) [Knight et al.,