X Linked Mental Retardation

Abstract

1. Height above the 97th percentile or below the 3rd percentile. 2. Head circumference above the 97th percentile or below the 3rd percentile.3. Fits necessitating continuous medication. 4. One major or two or more minor congenital abnormalities. 5. A definitive diagnosis. 6. Neurological signs.There were 17 individuals without abnormality. The family histories of these 17 moderately retarded males were then examined. 7 of them had a similarly affected brother. In 4 there was a positive family history compatible with X-linkage, without an affected male sibling. Therefore, in 11 out of the 17 (65%) there was either an affected male sibling or a family history compatible with X-linkage. In none of the families was ^ere an affected sister. The propositus being excluded, the ratio of affected brothers/normal 3.

Fragile (X) X‐linked mental retardation I: Relationship between age and intelligence and the frequency of expression of fragil (X)(q28)

“…The identification of the fra(X) "marker" in a form of X-linked mental retardation (fra(X)MR) has been a major insight into one of the common forms of mental handicap. The marker was first identified by Lubs [1969]; however, several years elapsed before the rediscovery of the fragile X on the X chromosome and detailed clinical delineation of the disorder by many independent investigators [Turner et al, 1975;Giraud et al, 1976;Harvey et al, 1977;Sutherland, 1977;Sutherland and Ashford, 1979;Howard-Peebles and Stoddard, 1979;Turner et al, 1980a;Jennings et al, 1980;Jacobs et al, 1980;Martin et al, 19801. Demonstration of the fra(X) was noted to be enhanced by a number of culture medium manipulations including reduced thymidine and folic acid [Sutherland, 1977;Howard-Peebles and Howell, 19791, the necessity for methionine [Howard-Peebles et al, 19801, and addition of folic acid antagonists [Glover, 1981;Tommerup et al, 1981al.…”