An Unexpected Detection of the Rare 48,XXYY in the Prenatal Diagnosis of a Fetus with β-Thalassemia Major.

BACKGROUND

Thalassemia is a common monogenic disorder, and children with β-thalassemia major require regular blood transfusions and iron removal therapy. Klinefelter syndrome (KS) is a common sex chromosome abnormality, and 48,XXYY is rare. This report is the first to describe a fetus with a karyotype of 48,XXYY in prenatal diagnosis of β-thalassemia major.

METHODS

Amniotic fluid was collected by puncture for the prenatal diagnosis of thalassemia, and chromosomal karyotyping was also performed. PCR and reverse dot-blot hybridization (PCR-RDB) were used to identify 17 common β-thalassemia mutations in China. Karyotype analysis of amniotic fluid was performed.

RESULTS

The results of PCR-RDB revealed that the genotype of the fetus was a homozygote of CDs41-42 (-TTCT) in the HBB gene. The karyotype analysis displayed that the fetus had Klinefelter syndrome (KS), and the karyotype was the rare 48,XXYY. The fetus was diagnosed with β-thalassemia major and KS.

CONCLUSIONS

An unexpected detection of the rare 48,XXYY in the prenatal diagnosis of a fetus with β-thalassemia major. There is a pitfall of genetic counseling and prenatal diagnosis in China.