Peng Can, LinPeng SiYuan, Bu Xiufen, Jiang XuanYu, Hu LanPing, He Jun, Zhou ShiHao
Department of Genetics and Eugenics, Changsha Hospital for Maternal & Child Health Care Affiliated to Hunan Normal University, Changsha, 410007, Hunan, China.
Mol Cytogenet. 2022 Jun 27;15(1):25. doi: 10.1186/s13039-022-00602-4.
Tetrasomy 18p syndrome is a rare chromosomal disorder that is caused by the presence of isochromosome 18p. Most tetrasomy 18p cases are de novo cases and maternal origin of trisomy 18p is a rare condition. At present, only four cases of maternal origin have been reported in worldwide.This is the fifth case of tetrasomy 18p originating from maternal trisomy 18p. The mother of the fetus studied had no apparent disease phenotype.
The current case report is to describe a fetus with confirmed 18p tetrasomy as detected by karyotyping and Single Nucleotide Polymorphism array (SNP array) analysis. However, the fetus showed normal phenotypic features that were observed using ultrasound scans. The mother and maternal grandfather were phenotypically normal and healthy; however, they were diagnosed with trisomy 18p, which was confirmed by conventional karyotyping and SNP array.
We report a case of 18p tetrasomy in a fetus whose mother and grandfather had 18p trisomy. The mother and grandfather were phenotypically normal. Our case report findings provide an important reference for the genetic counseling of trisomy 18p in the future.
18p四体综合征是一种罕见的染色体疾病，由18号染色体短臂等臂染色体引起。大多数18p四体病例为新发病例，18p三体源自母亲的情况较为罕见。目前，全球仅报道了4例源自母亲的病例。这是第5例源自母亲18p三体的18p四体病例。所研究胎儿的母亲没有明显的疾病表型。
本病例报告旨在描述一例经核型分析和单核苷酸多态性阵列（SNP阵列）分析确诊为18p四体的胎儿。然而，通过超声扫描观察到该胎儿表现出正常的表型特征。母亲和外祖父表型正常且健康；然而，他们经传统核型分析和SNP阵列确诊为18p三体。
我们报告了一例胎儿18p四体的病例，其母亲和外祖父患有18p三体。母亲和外祖父表型正常。我们的病例报告结果为未来18p三体的遗传咨询提供了重要参考。
