Partial trisomy 16q and partial monosomy 7p of a fetus derivated from paternal balanced translocation

Abstract

Introduction: Subchromosomal deletions and duplications could currently be detected by noninvasive preliminary screening (NIPS). However, NIPS is a screening test that requires further diagnosis. Here we report a fetus with an autosomal abnormality revealed by NIPS and conventional karyotype combined with copy number variations sequencing (CNV-seq) confirmed the fetus with an unbalanced translocation. Patient concern: This was the fourth pregnancy of a 30-year-old woman who underwent 2 spontaneous abortions and gave birth to a child with a normal phenotype. The woman and her husband were healthy and nonconsanguineous. NIPS indicated a repeat of about 19-Mb fragment at the region of 16q22.1-q22.4 at 17-week gestation. Diagnoses: The combination of traditional karyotype and CNV-seq could better locate the abnormal chromosomal region and further identify the source of fetal chromosomal abnormalities. Simultaneously, we evaluated the fetal morphology by ultrasound examination. The karyotype of the fetus was 46,XX,der(7)t(7;16)(p22;q23) and CNV-seq results showed an approximately 20.96-Mb duplication in 16q22.1-q24.3 (69200001-90160000) and an approximately 3.86-Mb deletion in 7p22.3-p22.2 (40001-3900000). Prenatal ultrasound revealed the fetal micrognathia. The paternal karyotype was 46,XY, t (7;16) (p22;q23), while the maternal was normal. The fetus inherited an abnormal chromosome 7 from its father. Interventions: No treatment for the fetus. Outcomes: Pregnancy was terminated. Conclusions: To our knowledge, the occurrence of de novo partial trisomy 16q (16q22.1-qter) and partial monosomy 7p (7p22.2-pter) has not previously been reported up to now. Here, we present the perinatal findings of such a case and a review of the literatures. CNV-seq combined with karyotype is a useful tool for chromosomal abnormalities indicated by NIPS.

Partial trisomy 9p and partial monosomy 7p of an infant inherited from maternal balanced translocation: a case report

“…Another possibility may be due to its coexistence with a heterozygous deletion of approximately 3.30 Mb in the 7p22.2p22.3 region, which contains 30 OMIM genes including 11 morbidity-associated genes ( BRAT1 , FAM20C, EIP3B , LFNG , INTS1 , etc.). INTS1 and BRAT1 genes are located at 7p22.3 and are associated with uniform neurodevelopmental disorders [ 11 ]. It has been reported in the literature [ 12 ] that the main clinical phenotype of patients with 7p22.2p22.3 deletion is a peculiar facial appearance, with developmental delay in speech, etc.…”