Novel exon 11 skipping mutation in a patient with glycogen storage disease type IIId.
We report the molecular genetic abnormalities of a patient with GSD IIId presenting with progressive myopathy and cardiopathy leading to a fatal outcome. We identified two independent deletions including a 4 bp deletion (117-1120) and a 98 bp deletion (1135-1232) in cDNA. Sequencing of the genomic DNA of the corresponding region revealed a 4 bp deletion in exon 10; however, the other 98 bp deletion corresponding to exon 11, which was deleted in cDNA, was present in genomic DNA. We therefore concluded that skipping of exon 11 occurred in the cDNA of the patient. Intron/exon boundary analysis of the skipped exon 11 revealed no mutation in the consensus splice-site sequence. If normal splicing had occurred, a stop codon would have appeared within exon II due to frameshift mutation. The mechanism of exon skipping observed in our patient is as yet unknown, and it is still not clear whether intraexonal mutation of the preceding exon can influence splice-site selection. It is possible that a unique exon skipping occurred, preventing the appearance of a stop codon in our patient.
Sugie
H
H
Department of Pediatric Neurology, Neuromuscular Laboratory, Hamamatsu City Medical Center for Developmental Medicine, Hamakita City, Shizuoka, Japan. hattatsu@city.hamamatsu.shizuoka.jp
Fukuda
T
T
Ito
M
M
Sugie
Y
Y
Kojoh
T
T
Nonaka
I
I
D000328:Adult; D009202:Cardiomyopathies / Q000235:genetics / Q000473:pathology; D017931:DNA Primers; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D018450:Disease Progression; D004587:Electrophoresis, Agar Gel; D005091:Exons / Q000235:genetics*; D017809:Fatal Outcome; D005260:Female; D006004:Glycogen Debranching Enzyme System / Q000235:genetics; D006010:Glycogen Storage Disease Type III / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008099:Liver / Q000201:enzymology; D018482:Muscle, Skeletal / Q000201:enzymology; D009135:Muscular Diseases / Q000235:genetics / Q000473:pathology; D009154:Mutation / Q000235:genetics*; D009206:Myocardium / Q000201:enzymology / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D018076:DNA, Complementary; D006004:Glycogen Debranching Enzyme System; D012333:RNA, Messenger