目的:我们提出了妊娠中家族性3p26.3p25.3缺失的产前诊断,该诊断与三代胎儿结局良好且无症状的携带者父母和家庭成员相关。
方法:35岁,gravida2,第1段,女性在妊娠17周时接受了羊膜穿刺术,原因是产妇年龄高和远端3p缺失的携带者。她的表型正常,没有先天性异常的家族史。羊膜穿刺术显示核型为46,XY,del(3)(p26.1)。在妊娠21周时重复羊膜穿刺术显示核型为46,XY,del(3)(p25.3)。对从未培养的羊膜细胞提取的DNA进行的同时阵列比较基因组杂交(aCGH)分析显示,ARR3p26.3p25.3(117,735-8,709,972)×1.0[GRCh37(hg19)]的结果为8.59-Mb缺失3p26.3p25.3,包含14个OMIM基因CHL1,CNTN6,CNTN4,IL5RA,TRNT1、CRBN、SETMAR,SUMF1,ITPR1,BHLHE40,ARL8B,GRM7、LMCD1和SSUH2。父母血液的细胞遗传学分析显示核型为46,XX,del(3)(p25.3)在母亲和46,XY在父亲。通过常规细胞遗传学分析,该妇女的69岁母亲和2岁大儿子携带相同的异常染色体3p25.3→p26.3缺失,但未表现出表型异常。aCGH对外围血液的分析表明,该妇女的母亲和她的大儿子有相同的8.59-Mb删除3p26.3p25.3。建议该妇女继续怀孕。妊娠39周时,一名3040克健康男婴分娩。在2½岁时进行随访时,新生儿发育正常,无明显表型异常。
结论:涉及从CHL1到SSUH2的OMIM基因的3p26.3p25.3的远端3p缺失可能与没有明显的表型异常有关。
OBJECTIVE: We present prenatal diagnosis of familial 3p26.3p25.3 deletion in a pregnancy associated with a favorable fetal outcome and asymptomatic carrier parent and family members in three generations.
METHODS: A 35-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age and the carrier of distal 3p deletion. She was phenotypically normal, and there was no family history of congenital anomalies. Amniocentesis revealed a karyotype of 46,XY,del(3)(p26.1). Repeat amniocentesis at 21 weeks of gestation revealed a karyotype of 46,XY,del(3)(p25.3). Simultaneous array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes showed the result of arr 3p26.3p25.3 (117,735-8,709,972) × 1.0 [GRCh37 (hg19)] with an 8.59-Mb deletion of 3p26.3p25.3 encompassing 14 OMIM genes of CHL1, CNTN6, CNTN4, IL5RA, TRNT1, CRBN, SETMAR, SUMF1, ITPR1, BHLHE40, ARL8B, GRM7, LMCD1 and SSUH2. Cytogenetic analysis of parental bloods revealed a karyotype of 46,XX,del (3) (p25.3) in the mother and 46,XY in the father. The woman\'s 69-year-old mother and her 2-year-old elder son carried the same aberrant chromosome of 3p25.3→p26.3 deletion by conventional cytogenetic analysis but manifested no phenotypic abnormality. aCGH analysis of the peripheral bloods showed that the woman\'s mother and her elder son had the same 8.59-Mb deletion of 3p26.3p25.3. The woman was advised to continue the pregnancy. At 39 weeks of gestation, a 3040-g healthy male baby was delivered. When follow-up at age 2½ years, the neonate was normal in development and showed no apparent phenotypic abnormality.
CONCLUSIONS: Distal 3p deletion of 3p26.3p25.3 involving the OMIM genes from CHL1 to SSUH2 can be associated with no apparent phenotypic abnormality.