[Retrospective study of nine Lebanese families with fragile X syndrome and review of the literature].

The Fragile X syndrome is the most common inherited form of mental retardation. Despite its incidence, which is estimated at 1/4000 boys, only 9 families have been documented so far in Lebanon, of which 3 have been partially investigated. This syndrome therefore seems to be largely ignored by physicians. Although no treatment is yet available for the Fragile X syndrome, the diagnosis of the disorder in a child is essential in order to provide the family with genetic counselling. The most critical point is still to convince the family of the need for such an evaluation and relieve the parents of any feeling of guilt.