[Genotype and phenotype studies on fetuses of 22q11.2 deletion syndrome].

OBJECTIVE

To study the genotype and phenotype of fetuses with 22q11.2 microdeletion and other abnormalities such as cardiac malformation and cleft palate.

METHODS

Fetal ultrasound was carried out at 12 weeks to 20 to 24 weeks of gestation. After excluding the chromosomal karyotype abnormality, single nucleotide polymorphism (SNP) array was used to detect copy number variations of 5 fetuses with heart development abnormality or other structural abnormalities. The fetus with 22q11.2 microdeletion and its parents were also subjected to multiplex ligation-dependent probe amplification (MLPA) assay.

RESULTS

SNP array analysis showed that the 5 fetuses had all carried a 2.27-3.02 Mb deletion of the 22q11.2 region. MLPA assay confirmed that LCR22-A-B was involved in all cases, and that all deletions were de novo in origin.

CONCLUSION

It is of great significance to exclude 22q11.2 microdeletions in fetuses with cardiac malformations. The deletion regions of these fetuses are similar but different, and the phenotypic difference is related to their genotypes.