The SHOX region and its mutations.
The short stature homeobox-containing (SHOX) gene lies in the pseudoautosomal region 1 (PAR1) that comprises 2.6 Mb of the short-arm tips of both the X and Y chromosomes. It is known that its heterozygous mutations cause Leri-Weill dyschondrosteosis (LWD) (OMIM #127300), while its homozygous mutations cause a severe form of dwarfism known as Langer mesomelic dysplasia (LMD) (OMIM #249700). The analysis of 238 LWD patients between 1998 and 2007 by multiple authors shows a prevalence of deletions (46.4%) compared to point mutations (21.2%). On the whole, deletions and point mutations account for about 67% of LWD patients. SHOX is located within a 1000 kb desert region without genes. The comparative genomic analysis of this region between genomes of different vertebrates has led to the identification of evolutionarily conserved non-coding DNA elements (CNE). Further functional studies have shown that one of these CNE downstream of the SHOX gene is necessary for the expression of SHOX; this is considered to be typical "enhancer" activity. Including the enhancer, the overall mutation of the SHOX region in LWD patients does not hold in 100% of cases. Various authors have demonstrated the existence of other CNE both downstream and upstream of SHOX regions. The resulting conclusion is that it is necessary to reanalyze all LWD/LMD patients without SHOX mutations for the presence of mutations in the 5'- and 3'-flanking SHOX regions.
Genomic Research Center, Cante di Montevecchio Association ONLUS, Fano, PU, Italy.
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D041321:Chromosomes, Human, X / Q000235:genetics; D041322:Chromosomes, Human, Y / Q000235:genetics; D005260:Female; D006130:Growth Disorders / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D010009:Osteochondrodysplasias / Q000235:genetics; D000074122:Short Stature Homeobox Protein
D018398:Homeodomain Proteins; C106071:SHOX protein, human; D000074122:Short Stature Homeobox Protein