Trisomy of the short stature homeobox-containing gene (SHOX) due to duplication/deletion of the X chomosome: clinical implications on the stature.
BACKGROUND
The karyotypes of 2 patients with abnormal stature and different phenotypes revealed one similar structural abnormality in the X chromosome by conventional cytogenetic studies and fluorescence in situ hybridization analysis (FISH). FISH strongly suggested the presence of two copies of the SHOX gene in the der(X) chromosome.


RESULTS
Patient 1 is a teenager girl with tall stature, behavioral disturbances and normal pubertal development. The abnormal X chromosome was present in all cells studied. Parent's karyotypes were normal. Patient 2 is a girl with gonadal dysgenesis, mild Turner syndrome phenotype and short stature. The karyotype was a mosaic 45,X/46,X,r(X) and der(X) chromosome presented in most metaphases of the cell lines. Parent's karyotypes were normal. Nearly all duplication of Xp and partial deletion of the long arm (Xq) from Xq27 or Xq21 to Xqter, in cases 1 and 2, respectively, were observed. In both patients, duplication of Xp translocated to deleted Xq occurred leading to a triplication of the pseudoautosomal region 1 (PAR1) where the SHOX gene is located (Xp22.3).


CONCLUSIONS
We propose that in some cases of trisomy for the SHOX gene, the effect of overdosage per se may affect the stature, even in patients with preserved ovarian function (case 1), and that estrogen deprivation may not always be a contributor for tall stature (case 2).
Del Rey
Graciela
G
Jasper
Héctor
H
Bengolea
Sonia Viviana
SV
Boywitt
Adriana
A
De Bellis
Rodolfo
R
Heinrich
Juan Jorge
JJ
D000293:Adolescent; D001827:Body Height / Q000235:genetics*; D002648:Child; D002872:Chromosome Deletion; D058674:Chromosome Duplication; D041321:Chromosomes, Human, X / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D000074122:Short Stature Homeobox Protein; D014314:Trisomy / Q000235:genetics*
D018398:Homeodomain Proteins; C106071:SHOX protein, human; D000074122:Short Stature Homeobox Protein