Early cardiac failure in a child with Becker muscular dystrophy is due to an abnormally low amount of dystrophin transcript lacking exon 13.
Two Japanese brothers with Becker muscular dystrophy were shown by polymerase chain reaction (PCR) and cDNA sequence analysis to produce a dystrophin gene transcript lacking a single exon: that is, number 13. Despite having the same deletion mutation, the brothers showed clearly different clinical phenotypes: the younger brother developed cardiac failure at the age of nine, while the elder brother was asymptomatic. As alternative splicing was not responsible for this clinical difference, the amount of dystrophin transcript was examined by using reverse transcription semi-nested and parallel PCR. The results showed that the amount of the dystrophin transcript in the younger brother was 20% of that of the elder brother. This finding suggested that lesser amount of dystrophin transcript in the younger brother was responsible for the early onset of cardiac failure. This would represent a novel molecular mechanism for dystrophinopathy.
Ishigaki
C
C
Division of Genetics, International Center for Medical Research, Kobe, Japan.
Patria
S Y
SY
Nishio
H
H
Yoshioka
A
A
Matsuo
M
M
D002303:Cardiac Output, Low / Q000235:genetics*; D002648:Child; D016189:Dystrophin / Q000235:genetics*; D005091:Exons; D006801:Humans; D008297:Male; D009136:Muscular Dystrophies / Q000235:genetics*; D017384:Sequence Deletion; D014158:Transcription, Genetic
D016189:Dystrophin