Genetic Analysis of 1p36 Deletions for Six Aborted Fetuses.

CONTEXT: Chromosomal abnormalities in embryos are the most common cause of early spontaneous abortions. Chromosome 1p36 deletion syndrome (OMIM 607872) is the most common subtelomeric, terminal microdeletion syndrome.

OBJECTIVE

The study intended to analyze miscarriage samples using chromosomal microarray analysis (CMA), to explore the mechanism of chromosomal aberrations, and to identify the recurrence risk and a prenatal diagnostic strategy for couples experiencing spontaneous abortions.

DESIGN

The research team performed a narrative review by searching PubMed databases. The search used the keywords 1p36 deletion, CMA, karyotype analysis, FISH and aborted fetus. The team also conducted case studies using genetic analyses.

SETTING

The study took place at Wuxi Maternity and Child Health Care Hospital in Wuxi, Jiangsu, PR China.

PARTICIPANTS

Out of 673 abortion samples, six had 1p36 deletions (0.89%). Participants were the six families who had had those spontaneous abortions.

OUTCOME MEASURES: The research team evaluated the fetal samples using: (1) CMA, (2) karyotype analysis, and (3) novel fluorescence in-situ hybridization (FISH).

RESULTS

The CMA showed that: (1) fetus 1 had a 1.75 MB microdeletion at the 1p36.32p36.31 band, which testing didn't detect in fetus 1's parents, but the research team couldn't exclude the possibility that one of the parents was a carrier of a chromosomal insertional translocation; and (2) fetus 2 had a 5.10 MB microdeletion at the 1p36.13p36.12 segment, and fetus 3 had a 9.21 MB deletion at the 1p36.33p36.22 band, and the high-resolution karyotype analysis and FISH of the parents of both fetuses appeared normal, indicating that the chromosomal abnormalities were de novo; (3) fetus 4 had a 9.28 MB deletion at 1p36.33p36.22, although the high-resolution karyotype analysis of fetus 4's parent was normal; (4) fetuses 5 and 6 had a 7.64 MB microdeletion at 1p36.33p36.23 and a 4.45 MB deletion at 1p36.33p36.32, respectively, although the parents of both fetuses waived further testing.

CONCLUSIONS

This study provides the first report of recurrent spontaneous and sporadic abortions with 1p36 deletion syndrome. The CMA combined with a reasonable family-pedigree investigation can detect cryptic chromosomal aberrations in miscarriages and can determine the mechanism of the chromosomal variations. It thus is invaluable in assessing recurrence risk and providing appropriate prenatal diagnostic strategies for affected families.