Multiple mechanisms and multiple populations
We congratulate the authors for the very descriptive study of mechanisms implicated in the development of Sotos syndrome. The different mechanism studied in their population and comparison to the Japanese is very interesting. Their study group involves subjects mainly belonging to the UK, France, Germany, Italy, the USA and Australia. As there is no mention of the ethnic groups studied in the paper we presume that none of the subjects are Asian.
The authors mention ~10 % microdeletion as cause of Sotos syndrome in the UK as compared to large number of microdeletion cases in the Japanese group.
In the concluding paragraph the authors hypothesize differences in genome architecture in Japanese and non-Japanese population influencing microdeletion frequency. Would it be more appropriate to state Caucasian populations rather than non-Japanese as it would it be too early to presume that microdeletions do not occur at the same frequency in the Chinese or Indian subcontinent where more than 50% of the world population resides.
1. K Tatton-Brown, J Douglas, K Coleman, et al. Multiple mechanisms are implicated in the generation of 5q35 microdeletions in Sotos syndrome. J Med Genet 2005; 42: 307-313
2. Kurotaki N, Harada N, Shimokawa O et al. Fifty microdeletions among 112 cases of Sotos syndrome: Low copy repeats possibly mediate the common deletion. Hum Mutat 2003; 22:378–87