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Non-syndromic autosomal recessive mental retardation in Tunisian families : exclusion of GRIK2 and TUSC3 genes.

BACKGROUND
Mental retardation is one of the most frequent major handicap, with a 1-3 % frequency in the general population, it appear a major problem of public health. The recent progress of molecular biology and cytogenetic allowed to identify new genes for non syndromic autosomal recessive mental retardation (NSAR-MR).


AIM
Genetic analysis of NSAR-MR: the GRIK2 gene (6q16.3-q21) and the TUSC3 gene (8p22).


METHODS
Four Tunisian families with NSAR-MR were included in this study. Genotyping was made using polymorphic microsatellite markers and statistical analysis was validated using the Fast Link programme of the Easy linkage software (V4:00beta).


RESULTS
Genotyping and linkage analysis excluded linkage of the GRIK2 gene and TUSC3 gene.


CONCLUSION
Our results confirm the extreme genetic heterogeneity of NSAR-MR.