Prevalence of the fragile X syndrome in African-Americans.
Since the development of a molecular diagnosis for the fragile X syndrome in the early 1990s, several population-based studies in Caucasians of mostly northern European descent have established that the prevalence is probably between one in 6,000 to one in 4,000 males in the general population. Reports of increased or decreased prevalence of the fragile X syndrome exist for a few other world populations; however, many of these are small and not population-based. We present here the final results of a 4-year study in the metropolitan area of Atlanta, Georgia, establishing the prevalence of the fragile X syndrome and the frequency of CGG repeat variants in a large Caucasian and African-American population. Results demonstrate that one-quarter to one-third of the children identified with the fragile X syndrome attending Atlanta public schools are not diagnosed before the age of 10 years. Also, a revised prevalence for the syndrome revealed a higher point estimate for African-American males (1/2,545; 95% CI: 1/5,208-1/1,289) than reported previously, although confidence intervals include the prevalence estimated for Caucasians from this (1/3,717; 95% CI: 1/7,692-1/1,869) and other studies. Further population-based studies in diverse populations are necessary to explore the possibility that the prevalence of the fragile X syndrome differs among world populations.
Crawford
Dana C
DC
Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Meadows
Kellen L
KL
Newman
James L
JL
Taft
Lisa F
LF
Scott
Elizabeth
E
Leslie
Mary
M
Shubek
Lisa
L
Holmgreen
Patricia
P
Yeargin-Allsopp
Marshalyn
M
Boyle
Coleen
C
Sherman
Stephanie L
SL
D000483:Alleles; D044383:Black People / Q000235:genetics*; D002648:Child; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1; D005600:Fragile X Syndrome / Q000453:epidemiology / Q000235:genetics*; D005787:Gene Frequency; D006801:Humans; D008297:Male; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics; D015995:Prevalence; D016601:RNA-Binding Proteins; D018911:Trinucleotide Repeats / Q000235:genetics; D014481:United States / Q000453:epidemiology; D001741:Black or African American
D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C497683:FMR1 protein, human