ABSTRACT
OBJECTIVE@#To investigate the perinatal clinical phenotype and genetic characteristics of two fetuses with ring chromosome 21 mosaicisms.@*METHODS@#Two fetuses who were diagnosed at the Xiamen Maternal and Child Health Care Hospital in November 2021 were selected as the study subjects. Clinical data of the two fetuses were collected. Conventional G-banded karyotyping and chromosomal microarray analysis (CMA) were carried out for the fetuses and their parents.@*RESULTS@#Prenatal ultrasonography of fetus 1 has revealed absence of nasal bone, ventricular septal defect, persistent left superior vena cava, and mild tricuspid regurgitation. Chromosomal karyotyping was 46,X?,dic r(21;21)(p12q22;q22p12)[41]/45,X?,-21[9]. CMA has revealed a 30.00 Mb quadruplication at 21q11.2q22.3 and a 3.00 Mb deletion at 21q22.3. For fetus 2, ultrasonography has revealed pointed echo of the nasal bone. The fetus was found to have a karyotype of 46,X?,r(21)(p12q22)[83]/45,X?,-21[14]/46,X?,dic r(21;21)(p12q22;q22p12)[3]. CMA has revealed a 5.10 Mb quadruplication at 21q22.12q22.3 and a 2.30 Mb deletion at 21q22.3.@*CONCLUSION@#The perinatal phenotype of the two fetuses with ring chromosome 21 mosaicisms is related to the duplication of chromosomal segments near the breakpoints of the chromosomal deletions. The combined chromosomal karyotyping and CMA has enabled prenatal diagnosis and genetic counseling for these families.
Subject(s)
Pregnancy , Female , Humans , Mosaicism , Ring Chromosomes , Vena Cava, Superior , Chromosome Aberrations , Prenatal Diagnosis , Microarray Analysis , Fetus/diagnostic imagingABSTRACT
Objective@#To explore the genetic basis for a case of recurrent fetal congenital hydrocephalus.@*Methods@#Next-generation sequencing was carried out for the fetus, the gravida and two of her sisters.@*Results@#The fetus was found to harbor a c. 1765T>C (p.Tyr589His) mutation in exon 14 of the L1CAM gene, which was derived from the gravida.@*Conclusion@#Male fetuses with recurrent hydrocephalus should be subjected to testing of the L1CAM gene to facilitate genetic counseling and prenatal diagnosis.
ABSTRACT
OBJECTIVE@#To explore the genetic basis for a case of recurrent fetal congenital hydrocephalus.@*METHODS@#Next-generation sequencing was carried out for the fetus, the gravida and two of her sisters.@*RESULTS@#The fetus was found to harbor a c.1765T>C (p.Tyr589His) mutation in exon 14 of the L1CAM gene, which was derived from the gravida.@*CONCLUSION@#Male fetuses with recurrent hydrocephalus should be subjected to testing of the L1CAM gene to facilitate genetic counseling and prenatal diagnosis.