摘要本文报道1个家系既往2次足月分娩活男婴，新生儿均无窒息，但分别于生后第5天和第13天死亡，父母染色体核型分析均未见异常。详细了解既往2个新生儿的临床表现及相关检测结果，对新生儿2保留的干血片进行全外显子组测序，发现甲基丙二酰辅酶A变位酶基因（NM_000255）c.729_730insTT纯合变异（p.D244Lfs*39），明确新生儿2为甲基丙二酸血症。本次妊娠孕20周 +3行羊膜腔穿刺，行羊水Sanger测序，提示胎儿存在与新生儿2相同的纯合变异，生后表型应与新生儿2相同，为甲基丙二酸血症患儿，遂于孕24周引产终止妊娠。

abstractsThis article reports a pedigree with two previously deceased neonates. Both neonates did not experience asphyxia but passed away on their 5th and 13th day of life. The chromosomal analysis of the parents' karyotype revealed no abnormalities. Clinical manifestations of the two deceased cases and relevant medical records were recollected. Whole exome sequencing was conducted on the stem blood sample of Neonate 2, revealing a c.729_730insTT homozygous mutation (p.D244Lfs*39) in the methylmalonyl-CoA mutase gene (NM_000255). It was confirmed that Neonate 2 was affected with methylmalonic acidemia. Amniocentesis was performed at 20 +3 weeks in the current pregnancy. Sanger sequencing of amniotic fluid indicated that the fetus carried the same gene mutation as Neonate 2. Consequently, the fetus was expected to be a patient with methylmalonic acidemia and to exhibit the same phenotype as Neonate 2. Termination of pregnancy, therefore, was selected at 24 weeks of gestation.