Pediatric Medical Genetics - S.I. Smiian 2003

Chromosomal diseases
Triple-X syndrome

Trisomy X syndrome occurs more frequently in newborn girls than Turner syndrome (1:1200). It was first described by Patricia Jacobs et al. in 1959.

This condition is characterized by a specific chromosomal set of 47 Chromosomes, featuring three X chromosomes (47,XXX). Conversely, an increased number of X chromosomes reduces gonadal activity. This occurs because the extra X chromosome remains in an inactive, coiled state. This also explains why cellular balance is not significantly disrupted in terms of major pathological changes in Internal Organs. The 48,XXXX and 49,XXXX syndromes occur less frequently and are accompanied by severe intellectual disability.

Trisomy X syndrome lacks a distinct clinical picture. A physician may encounter either pronounced clinical manifestations or mild, latent forms of the condition.

Patients with triple X syndrome exhibit underdeveloped Ovaries, a hypoplastic Uterus, Infertility, irregular menstrual cycles, and a reduced number of primordial follicles; they experience early secondary Amenorrhea or premature menopause. Nevertheless, a third of these women retain their reproductive function and bear healthy children.

Women with the XXX chromosomal Complement fairly often present with mild intellectual impairment while maintaining relative emotional stability. Among them, individuals with psychopathic traits and a predisposition to schizophrenic disorders are several times more common. Many exhibit non-specific somatic dysmorphisms of varying severity. As the number of X chromosomes increases, clinical symptoms escalate sharply. Affected individuals are intellectually disabled and infertile.

Diagnosis is based on sex Chromatin analysis, which distinguishes patients with an abnormal X chromosome complement from those with primary endocrine pathology. The definitive diagnosis is established through cytogenetic testing.

Treatment is primarily symptomatic and aims to correct the endocrine imbalance, focusing above all on restoring ovarian function. The prognosis depends on the clinical manifestations of the disease.