Topographic pattern of the rearrangement of the dystrophin gene in Japanese Duchenne muscular dystrophy

Abstract

To compare the frequency and distribution of rearrangements in the dystrophin gene in Duchenne muscular dystrophy (DMD) between Japanese DMD patients and those in North America and Europe, Southern blot analyses of the dystrophin gene were carried out in 88 probands classified as DMD. Gene rearrangements were found in 61 (69%) subjects, and they were composed of partial gene deletions in 53 (60%) probands and partial duplications in 7 (8%) probands. A total deletion of the gene was found in 1 (1%) patient. Among 53 patients with deletions, 34 (64%) had breakpoints between introns 44 and 52 and 7 (13%) had breakpoints between introns 2 and 11. Both the frequency and the distribution of gene rearrangements found in this study were similar to those reported in North America and Europe. These data suggest that there are no ethnic or racial differences in the frequency and distribution of rearrangements thought to be caused by similar mechanisms in the dystrophin gene in all human racial groupings.

Are there ethnic differences in deletions in the dystrophin gene?

“…In the case of Japanese patients, frequency of deletions [43%, Sugino et al, 1989;43%, Tsukamoto et al, 1991] was lower than that observed in the present study and in studies in the US [Baumbach et al, 1989;Darras et al, 1988] and Europe [Hodgson et al, 1989;Gillard et al, 1989;Den Dunnen et al, 1989;Niemann-Seyde et al, 1992;Covone et al, 1992]. However, Imoto et al [1993] reported a higher frequency (60%). Tsukamoto et al [1991] studied only 28 patients and analyzed only nine exons.…”

“…From Table III it is clear that, whenever cDNA probes covering the whole gene were used for Southern analysis [Darras et al, 1988;Hodgson et al, 1989;Den Dunnen et al, 1989;Gillard et al, 1989;Baumbach et al, 1989;Imoto et al, 1993], or whenever most of the primers covering the two "hot spot" regions were used for PCR amplifications Niemann-Seyde et al, 1992; present study], the frequency of deletions observed was similar. Interestingly, Covone et al [1992] used 30 primer sets, and the frequency of deletions was almost the same as that in the present study, where 27 primer sets were used for PCR amplification.…”

“…Most mutations in the DMD gene are intragenic deletions (65%) or duplications (5%) [Koenig et al, 1988;Forrest et al, 1988;Hu et al, 1988]. A number of studies have documented the frequency and distribution of deletions in different parts of the world [Den Dunnen et al, 1989;Gillard et al, 1989;Chamberlain et al, 1992;Covone et al, 1992;Imoto et al, 1993], and some authors have suggested that these vary with ethnic origin [Sugino et al, 1989;Tsukamoto et al, 1991;Kádasi et al, 1991;Baranov et al, 1993;Ballo et al, 1994]. There have so far been only two small studies of exonal deletions among patients with DMD in India [Sinha et al, 1992;Saxena and Verma, unpublished results].…”

Duchenne muscular dystrophy: Study of double deletions and familial cases

“…The percentage of deletions (72.5%) seen in the present study matches with most Indian studies [13][14][15]17] and the sites of deletions are similar to the available information from studies of various populations [18][19][20][21][22][23][24][25][26].…”

Screening 25 Dystrophin Gene Exons for Deletions in Arab Children with Duchenne Muscular Dystrophy

“…Table 2 compares the detection rates published from Europe, North America and Asia. The detection rate from North American and European studies varied from 55 to 70% [12, 13, 14], while from Asia it was much lower, being 40–43% in Japan [15], 45–50% in Chinese DMD patients [16] and 55% in Thailand [17]. In all of these studies except one, only multiplex I or II or both or cDNA probes were used.…”