POSTERS

 

PM-42

Trisomy x syndrome (47,XXX) preventive management in pediatric age: case report

 

 

Saraiva T^I; Oliveira FP^II; Oliva Teles N^II; Fonseca e Silva ML^II; Fortuna AM^I

^ICentro de Genética Médica, Centro Hospitalar do Porto
^IIUnidade de Citogenética, Centro Hospitalar do Porto

 

 

Introduction: Trisomy X is a sex chromosome aneuploidy caused by the presence of an extra X chromosome in females (47,XXX). It is the most common female chromosomal abnormality, occurring in approximately 1 in 1,000 births. The cause for this chromosomal abnormality is a nondisjunction occurring during the meiotic period and it is connected to advanced maternal age.

Because of the mild and variable phenotypic expression of this condition, only 10% of individuals are diagnosed. The most common features are: tall stature, hypotonia and minor physical findings. As a group, children with this syndrome may have motor and speech delays, with an increased risk of cognitive deficits and learning disabilities. Seizures, renal abnormalities, congenital heart defects, premature ovarian failure, psychological disorders (anxiety, depression and psychotic disorders) and behavioral problems (immaturity and impaired psychosocial adaptation) have also been reported.

Case report and results: We describe a girl aged five with trisomy X syndrome referred for our Medical Genetics Centre for the confirmation of 47,XXX, previously diagnosed in prenatal amniocentesis due to advanced maternal age. She presents with tall stature, hypotonia in the first years and some social-emotional difficulties. Motor and speech delay has not been reported. Karyotype analysis of peripheral blood confirmed the trisomy X.

Conclusion: Karyotype analysis of peripheral blood is the most standard test used to make the diagnosis of Triple X. It is recommended that patients identified in prenatal diagnosis confirm results after birth.

Infants and children should undergo evaluation for both psychological and medical features of this disorder. Renal ultrasound, cardiac evaluation, ophthalmological investigation and EEG might be indicated. These patients should also be followed closely for developmental delay so that early intervention therapies may be adequately implemented. Pubertal development is normal in the majority of patients. However, adolescents presenting with late menarche/menstrual irregularities should be evaluated by Endocrinology. Autoimmune (e.g., thyroid) abnormalities should also be considered.

The prognosis is variable, depending on severity of manifestations and quality/timing of treatment. Genetic counseling is recommended, with families being informed about the sporadic nature of the chromosome anomaly, the wide variability in phenotype, and low risk of recurrence (<1-5%).