Abstract:

Deletion of the proximal long arm of chromosome 6 is a rare chromosomal disorder, which is typically characterized by intellectual disability, developmental delay and abnormal facial features. The genetic etiology of a case of multiple malformation fetus was reviewed. The patient underwent amniocentesis at the 21⁺¹ week of gestation, following findings of multiple fetal malformations indicated by ultrasound and high risk of fetal chromosome 6 abnormality indicated by noninvasive prenatal testing (NIPT). Routine G-banding chromosome karyotype analysis and copy number variation sequencing (CNV-seq) were performed. At the same time, the chromosome karyotypes of the parents were detected. Routine G-banding chromosome karyotype analysis of amniotic fluid showed 46,XX,del(6)(q14q16); CNV-seq results of amniotic fluid showed 23.68 Mb deletion in 6q14.1q16.3(80960000-104640000) region. Combining the above results, it is considered that the deletion is the cause of multiple fetal malformations. CNV-seq proves valuable in identifying the break point of fetal chromosome abnormalities, providing a basis for predicting the risk of fetal malformation and subsequent genetic counseling and enriching the prenatal clinical manifestations of 6q deletion.

Key words: 6q14.1q16.3 deletion, Abnormalities, multiple, DNA copy number variations, Karyotyping, Copy number variation sequencing