A case of double aneuploidy of Down and Klinefelter syndrome in an Indian infant: a detailed case report

Abstract Background A variation in the number of chromosomes can lead to chromosomal disorders. These chromosomal aberrations might be related to autosomes or sex chromosomes. The most common chromosomal aberrations that are sex-linked and autosomal are Klinefelter syndrome and Down syndrome, respectively. However, the worldwide occurrence of double chromosomal aneuploidy in a single individual is relatively exceptional event and random meiotic nondisjunction events result in double aneuploidy, which causes trisomy of two distinct chromosomes. The clinical manifestations vary depending on whether aneuploidy is dominant or an amalgam of both. Moreover, double aneuploidy including autosome and sex chromosome is not often documented. In this paper, we document a case of Down–Klinefelter double aneuploidy syndrome in an Indian infant hospitalized to the neonatal care unit. Case presentation A full-term 9-month-old male infant born to a 36-year-old female with classical clinical signs of Down syndrome like epicanthus, a depressed nasal bridge, a flat face, small ears, an open mouth, thick lower lip vermilion, a protruding tongue, and a short neck was referred for cytogenetic examination, revealing a rare karyotype of 48, XXY, + 21. Conclusion Down–Klinefelter syndrome is a rare chromosomal anomaly with unique characteristics, often displaying only Down syndrome-like traits at birth. Early diagnosis can be challenging due to the lack of noticeable symptoms until puberty. Early cytogenetic investigation can detect double aneuploidy, improving the affected person's quality of life and educating family members about potential medical and psychosocial difficulties.