Fragile X syndrome without CCG amplification has an FMR1 deletion.
We describe a patient with typical clinical features of the fragile X syndrome, but without cytogenetic expression of the fragile X or an amplified CCG trinucleotide repeat fragment. The patient has a previously uncharacterized submicroscopic deletion encompassing the CCG repeat, the entire FMR1 gene and about 2.5 megabases of flanking sequences. This finding confirms that the fragile X phenotype can exist, without amplification of the CCG repeat or cytogenetic expression of the fragile X, and that fragile X syndrome is a genetically homogeneous disorder involving FMR1. We also found random X-inactivation in the mother of the patient who was shown to be a carrier of this deletion.
Gedeon
A K
AK
Department of Cytogenetics and Molecular Genetics, Adelaide Children's Hospital, South Australia.
Baker
E
E
Robinson
H
H
Partington
M W
MW
Gross
B
B
Manca
A
A
Korn
B
B
Poustka
A
A
Yu
S
S
Sutherland
G R
GR
D000328:Adult; D001483:Base Sequence; D002478:Cells, Cultured; D002871:Chromosome Banding; D002874:Chromosome Mapping; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1; D005600:Fragile X Syndrome / Q000235:genetics*; D017353:Gene Deletion; D006801:Humans; D007621:Karyotyping; D008214:Lymphocytes / Q000502:physiology; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010375:Pedigree; D016601:RNA-Binding Proteins; D012091:Repetitive Sequences, Nucleic Acid; D014960:X Chromosome
D051860:Fragile X Messenger Ribonucleoprotein 1; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C497683:FMR1 protein, human