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The 48, XXXX/49,XXXXY/49,XXXX,i(Yq) mosaicism in a 3-year-old boy from a twin pregnancy

B Kaluzewski, D Podkul, I Zaborowska

    Human Genetics
    |July 26, 1977
    PubMed

    Insights

    This case report details a boy with developmental delays and congenital anomalies, diagnosed with a rare chromosomal abnormality (XXXX/XXXXY/XXXX,i(Yq) karyotype). The findings highlight the genetic basis of complex developmental disorders in twins.

    Area of Science:

    • Genetics
    • Developmental Biology
    • Pediatrics

    Background:

    • This report focuses on a rare case of a male twin exhibiting significant congenital anomalies and developmental deficits from birth.
    • The patient presented with dystrophia, growth deficiency, physical and mental retardation, multiple somatic defects, suspected congenital heart disease, and hypoplastic genitalia.

    Observation:

    • The affected twin was diagnosed with a complex chromosomal abnormality, specifically a mosaic karyotype of 48,XXXX/49,XXXXY/49,XXXX,i(Yq).
    • His normally developed dizygotic twin brother had a standard 46,XY karyotype.
    • Serologic testing confirmed the twins were dizygotic.

    Findings:

    • The study identifies a rare chromosomal aneuploidy in a male twin presenting with severe developmental and physical abnormalities.
    • The case highlights the potential for significant phenotypic variation even within dizygotic twin pairs due to distinct genetic compositions.

    Implications:

    • This case contributes to understanding the spectrum of clinical manifestations associated with complex sex chromosome aneuploidies.
    • It underscores the importance of comprehensive genetic evaluation in cases of severe congenital anomalies and developmental delays, particularly in twin gestations.
    • Further research into the mechanisms linking specific karyotypes to complex phenotypes is warranted.

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