Short stature homeobox
The pseudoautosomal region (PAR1) contains an interval of 170 kb that tends to be deleted in individuals with short stature and different rearrangements on Xp22 or Yp11.3. SHOX (Short stature HOmeoboX-containing gene) a homeo box-containing gene located in the PAR1, has at least 2 alternatively spliced forms encoding proteins with different patterns of expression. SHOX is involved in idiopathic growth retardation and in the short stature phenotype of Turner syndrome patients. The 2 mRNAs, SHOXa and SHOXb, code for proteins of 292 and 225 amino acids, respectively. Both transcripts have a common 5' end, diverging after exon IV. The SHOX gene is composed of 6 exons ranging in size from 58 bp to 1,146 bp. SHOX is highly conserved across species. The absence of the SHOX gene may be responsible for the growth failure in Turner syndrome females.