Genetic examination results of the family
Karyotype analysis of the proband showed 46,XX,der(18) karyotype with a derivative 18 chromosome. CMA identified a 25.6 Mb duplication of 8q24.12-q24.3 (ranging from position 120,721,382 to 146,295,771) and a 16.5 Mb deletion of 18q21.33-q23 (ranging from position 61,544,455 to 78,013,728) for the proband [Figure 2 (A, B)] and normal CMA results for her parents [Figure 2 (E, F)]. To trace the origin of the derivative 18 chromosome and abnormal CNVs of the proband, karyotype analysis of her parents were performed. It was found that the mother showed 46,XX karyotype [Figure 3 (F)], whereas the father was revealed to be a carrier of balanced RCT with 46,XY,t(8;18)(q23;q21.3) karyotype [Figure 3 (C, D)]. Taking together, the karyotype of the proband was finally to be recognized as 46,XX,der(18)t(8;18)(q24.1;q21.3)pat with a derivative 18 chromosome [Figure 3 (A, B)]. Results of CMA and karyotype analysis of amniotic fluid cells were the same as that of the proband [Figure 2 (C, D), Figure 3 (E)]. The couple decided to terminate the pregnancy after genetic counseling.