Genotype- phenotype correlation in trisomy X: a retrospective study of a selected group of 36 patients and review of literature.

Trisomy X (47,XXX) is a gonosomal aneuploidy characterized by the presence of an extra X chromosome in a female person. Usually the diagnosis is established made postnatally by chromosome analysis in patients with suggestive clinical signs. Clinical signs vary by age. In prepubertal patients have a growth retardation associated with uncharacteristic facial dysmorphism, mild mental retardation with behavioral disorders, plus clinical signs of ovarian dysgenesis, postpubertal. Aim: We analyzed  retrospectively the genotype - phenotype correlations for a selected group of 36 patients diagnosed with  trisomy  X (homogeneous or mosaic) by cytogenetic methods (X chromatin and karyotype). Material and methods: Analysis of the clinical data of 36 patients diagnosed with trisomy X and correlation with the results of X chromatin and karyotype. Results: Clinical signs detected in patients with homogeneous trisomy X 47,XXX (22.22%), mosaic 46,XX/47,XXX (16.66%) or 47,XXX/48,XXXX (5.55%) were prepubertal, growth retardation associated with dysmorphic facial (upslanted palpebral fissure, epichantus, thin lips) and postpubertal, signs of ovarian dysgenesis (secondary amenorrhea, early menopause). The phenotype of patients with different gonosomal mosaic corresponding to Turner syndrome, incorporating a cell line with trisomy X (55.55%) was variable, correlated with the type of chromosomal abnormalities detected. Conclusions: The results of our study are similar to those obtained in other studies and emphasizes that phenotypic variability of patients with trisomy X feature makes it difficult to genotype - phenotype correlations.