[Analysis of related phenotype of prenatal cases with copy number variations in various region of 22q11.2].

OBJECTIVE

To analyze the prenatal ultrasound phenotypes of copy number variations (CNVs) in different regions of 22q11.2, their parental original, and pregnancy outcome.

METHODS

Prenatal phenotypes of 25 cases with CNVs of the 22q11.2 region detected by chromosomal microarray analysis (CMA) was reviewed, which including There were 13 deletions and 12 duplications. Multiplex ligation-dependent probe amplification(MLPA) was carried out to determine their parental origin. All cases were followed up for their pregnancy outcome and postnatal growth.

RESULTS

Among the 25 cases, the ultrasound phenotypes of those involving the TBX1 gene were mostly cardiovascular system abnormalities, the ultrasound phenotypes of cases involving CRKL gene are mostly polycystic renal dysplasia. The ultrasound phenotypes of CNVs in the distal region (involving the SMARCB1 gene) are nervous system abnormalities. 12 cases (48%) of CNVs were de novo in origin. Five cases were lost during follow-up,12 had opted to terminate the pregnancy, 8 fetuses were born,7 with normal growth and development, 1 case with CNV in A-D region was abnormal.Prenatal ultrasound showed abnormalities in the cardiovascular system consistent with postnatal ultrasound, in addition with dysphagia and growth retardation.

CONCLUSION

Prenatal phenotypes of the 22q11.2 region CNVs are diverse, which may be related to gene function. NT thickening may be used as an early ultrasound finding of proximal 22q11.2 CNV. More research is still required to delineate the nature of CNVs and gene function, so as to facilitate genetic counseling.