Triple X syndrome.
1Department of Obstetrics & Gynaecology, Ziauddin Medical University, Karachi, Pakistan.
Summary
Triple X syndrome (47XXX) is a genetic condition with an extra X chromosome. Diagnosis in adulthood via chromosomal analysis revealed the cause of primary amenorrhea in one patient, with guarded fertility prognosis.
Area of Science:
- Genetics
- Reproductive Medicine
- Endocrinology
Background:
- Triple X syndrome, also known as 47XXX, is a chromosomal abnormality where females have an extra X chromosome.
- This condition is often asymptomatic at birth and may go undiagnosed until adulthood.
Observation:
- A young girl presented with primary amenorrhea, a condition where menstruation has not started.
- Clinical examination revealed no specific abnormalities.
Findings:
- Chromosomal analysis confirmed the diagnosis of Triple X syndrome (47XXX).
- The patient later experienced spontaneous menstrual cycles, but her long-term fertility remains uncertain.
Implications:
- This case highlights the importance of considering chromosomal abnormalities in cases of primary amenorrhea.
- Early diagnosis and genetic counseling are crucial for managing Triple X syndrome and addressing fertility concerns.
Related Concept Videos
01:19X-linked Traits
In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be masked by the presence of a normal allele on the second X. In contrast, a mutation on the X chromosome in males more often causes observable biological defects, as there is no normal X to compensate. Trait variations arising from mutations on the X chromosome are called “X-linked”.
01:19X-linked Traits
In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be masked by the presence of a normal allele on the second X. In contrast, a mutation on the X chromosome in males more often causes observable biological defects, as there is no normal X to compensate. Trait variations arising from mutations on the X chromosome are called “X-linked”.
01:43Sex-linked Disorders
Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.
01:58X-Inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
01:58X-inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
01:43Sex Linked Disorders
Like autosomes, sex chromosomes contain a variety of genes necessary for normal body function. When a mutation in one of these genes results in biological deficits, the disorder is considered sex-linked.