Résumé
Objective:To analyze the clinical phenotypes and prenatal diagnosis of a pedigree with oculo-facio-cardio-dental (OFCD) syndrome.Methods:A pregnant woman at 17 gestational weeks was admitted to the Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School in 2017 for genetic counseling. Genetic tests as performed for the proband (the pregnant woman), her husband, and the induced fetus of last pregnancy genetic test and the detected variants were analyzed and verified by chromosomal microarray analysis (CMA), multiplex ligation-dependent probe amplification (MLPA) and quantitative real time-polymerase chain reaction (Q-PCR). The detection platform established by MLPA and Q-PCR technology was used to perform prenatal diagnosis of the present pregnancy. Other family members were screened for BCOR gene mutation. Related mutation types were retrieved from ClinVar database with term of " BCOR", and related literature from CNKI and PubMed with terms of "OFCD syndrome", " BCOR gene", and "oculo facio cardiac dental syndrome" to summarize the clinical manifestations, mutation type and pathogenesis of this disease. Results:The proband has congenital cataracts, long face, congenital atrial septal defect, and severe dental malformations, which were consistent with the clinical features of OFCD syndrome. WES suggested that the proband and her induced fetus were suspected of having a large submicroscopic deletion of the exons of BCOR gene, which was confirmed by CMA, MLPA and Q-PCR, with a 105 kb deletion containing BCOR exons 1-15. The amniotic fluid genetic analysis of the present pregnancy showed that the fetus has a normal female karyotype, and did not carry the same BCOR gene copy number abnormality as the proband. The child grew and normally developed without any characteristic manifestations of OFCD syndrome during follow-up. Other families of the proband did not show clinical features of OFCD syndrone, and no BCOR gene copy number abnormality was detected. A total of 35 cases of BCOR gene mutation types related to OFCD syndrome were retrieved from ClinVar database. The data analysis revealed that the differences in clinical manifestations between Lenz microphthalmos syndrome and OFCD syndrome were mainly caused by different mutation types of BCOR gene. Among the 90 retrieved cases of OFCD syndrome obtained through literature, only one case was reported in China. Analysis of these 90 cases showed that the characteristic manifestations of OFCD syndrome, involving the eye, face, heart, teeth, and skeletal system. OFCD syndrome were confirmed in the proband and her induced fetus according to the clinical manifestation and the mutation type of BCOR gene. Conclusions:The clinical manifestations of OFCD syndrome are complicated, caused by various mutation types of BCOR. Systematic molecular genetic technology can be effectively applied for gene and prenatal diagnosis of OFCD syndrome.
Résumé
<p><b>OBJECTIVE</b>To carry out chromosomal microarray analysis (CMA) on four fetuses with abnormal karyotypes.</p><p><b>METHODS</b>Amniotic fluid samples were obtained and subjected to routine G-banded karyotyping analysis. CMA was applied for cultured amniocytes to determine alterations of gene dosage and chromosomal breakpoints.</p><p><b>RESULTS</b>Abnormal karyotypes were found in the parents of 3 fetuses. Parental karyotypes of the remaining fetus were normal. Imbalance chromosome rearrangements were revealed by CMA in all 4 cases.</p><p><b>CONCLUSION</b>CMA is an effective tool for the evaluation of clinical significance and delineation of the breakpoints involved in complex chromosomal rearrangements.</p>