Characterization of a deletion at Xq27-q28 associated with unbalanced inactivation of the nonmutant X chromosome.
We report the results of studies on the characterization of the mutation associated with marked unbalanced expression of the mutant X chromosome in a karyotypically normal girl with Hunter disease (mucopolysaccharidosis type II). Southern analysis of DNA extracted from somatic cell hybrids containing only the mutant X chromosome showed deletion of the Xq27.3-q28 loci: DXS297 (VK23AC), DXS293 (VK16), FRAXA (pfxa3), DXS296 (VK21A), and the 3' end of the iduronatesulfatase (IDS) gene. The flanking loci--DXS52 (St14-1), DXS304 (U6.2), and DXS369 (RN1)--were intact. On the basis of these results, we concluded that the mutation was a simple deletion extending a maximum of 3-5 cM to the centromeric side of the IDS gene. Both Southern analysis of DNA from somatic cell hybrids, using short segments of IDS cDNA, and PCR of reverse-transcribed RNA from cultured skin fibroblasts indicated that the telomeric terminus of the deletion was localized to a region near the middle of the coding sequences of the gene.
Clarke
J T
JT
Department of Pediatrics, Hospital for Sick Children, University of Toronto, Ontario, Canada.
Wilson
P J
PJ
Morris
C P
CP
Hopwood
J J
JJ
Richards
R I
RI
Sutherland
G R
GR
Ray
P N
PN
D001345:Autoradiography; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D002872:Chromosome Deletion; D004247:DNA; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007066:Iduronate Sulfatase / Q000235:genetics; D008969:Molecular Sequence Data; D016532:Mucopolysaccharidosis II / Q000235:genetics*; D009841:Oligonucleotides; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D014960:X Chromosome
D009841:Oligonucleotides; D012333:RNA, Messenger; D004247:DNA; D007066:Iduronate Sulfatase