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Prenatal diagnosis of a mosaic 46,XY/47,X,i(Xq)Y
J Alliet1, N Leporrier, C Lebris
1Laboratoire de Cytologie Génitale, Pr J. Izard, CHU, Côte de Nacre, Caen, France.
Prenatal Diagnosis
|January 1, 1989
Insights
This study reports the first case of mosaic isochromosome Xq in a boy, diagnosed prenatally and confirmed postnatally. This rare chromosomal abnormality involves a mixture of sex chromosome complements in the individual.
Area of Science:
- Human Genetics
- Reproductive Biology
- Cytogenetics
Background:
- Klinefelter syndrome (KS) is a common sex chromosome aneuploidy in males, typically presenting as 47,XXY.
- Structural rearrangements of the X chromosome in KS are less common but can lead to varied clinical presentations.
- Isochromosome Xq (i(Xq)) involves duplication of the long arm of the X chromosome, often leading to Turner syndrome in females.
Observation:
- A case of mosaicism involving a 46,XY cell line and a 47,X,i(Xq)Y cell line was identified at 18 gestational weeks via amniotic fluid cell analysis.
- The diagnosis was confirmed postnatally through lymphocyte analysis of the affected child.
- This represents a unique chromosomal configuration in a male infant.
Findings:
- The identified mosaic karyotype, 46,XY/47,X,i(Xq)Y, is a novel finding in the context of Klinefelter syndrome.
- This is the first reported instance of mosaic isochromosome Xq in a male patient.
- The review of literature highlights the rarity of structural X chromosome abnormalities in KS.
Implications:
- This case expands the known spectrum of chromosomal abnormalities associated with male sex development and potential disorders of sex development.
- Understanding such mosaic patterns is crucial for accurate genetic counseling and predicting clinical outcomes.
- Further research into the developmental impact and reproductive potential of individuals with i(Xq) mosaicism is warranted.
Abstract:
A case of mosaic 46,XY/47,X,i(Xq)Y is diagnosed at 18 gestational weeks in amniotic fluid cells and confirmed at birth in the lymphocytes of the child. The literature on Klinefelter's syndromes with structural chromosome X rearrangements is reviewed. This is the first case reported of a mosaic isochromosome Xq in a boy.