A fragile X male with a broad smear on Southern blot analysis representing 100-500 CGG repeats and no methylation at the EagI site of the FMR-1 gene.
Fragile X DNA studies were carried out on all obligate carriers of a large fragile X family with 10 mentally retarded individuals. One 64-year-old carrier man with an altered FMR-1 allele was not described as being mentally retarded or as having any limitations in function. He was married, raised 8 children, and worked as an auto mechanic. On examination, he had macrocephaly and mild macroorchidism but few of the other typical physical findings of males with fragile X syndrome. His Full Scale IQ is 73, and his Vineland Adaptive Behavior Composite is 73. On the Woodcock-Johnson Psycho-Educational Battery-Revised, he achieved standard scores of 64 in Reading, 55 in Math, and 83 in Knowledge. His DNA findings showed a broad smear on Southern blot analysis of 100-500 CGG repeats and no methylation at the EagI site upstream of the FMR-1 protein coding region. His FMR-1 protein production is 12% of normal. His daughters all have large premutations, with somatic instability in the size of the CGG repeat lengths. They all have evidence of academic underachievement and 2 have physical characteristics frequently described in individuals with fragile X.
Lachiewicz
A M
AM
Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710, USA.
Spiridigliozzi
G A
GA
McConkie-Rosell
A
A
Burgess
D
D
Feng
Y
Y
Warren
S T
ST
Tarleton
J
J
D015139:Blotting, Southern; D004247:DNA / Q000097:blood; D019175:DNA Methylation; D015252:Deoxyribonucleases, Type II Site-Specific; D005260:Female; D005600:Fragile X Syndrome / Q000235:genetics* / Q000503:physiopathology / Q000523:psychology; D006580:Genetic Carrier Screening; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D015183:Restriction Mapping; D018911:Trinucleotide Repeats
D004247:DNA; C046751:endodeoxyribonuclease XmaIII; D015252:Deoxyribonucleases, Type II Site-Specific