Prenatal Diagnosis and Molecular Cytogenetic Analyses of a Rare 17q12 Microdeletion and Microduplication in a Family with a Normal Phenotype.

BACKGROUND

Copy number variants (CNVs) contribute significantly to normal and pathogenic genomic variations. Chromosome 17q12 microdeletion is implicated in structural or functional kidney and urethral abnormalities, MODY5 (type 5 diabetes), and neurodevelopmental or neuropsychiatric disorders. Conversely, microduplication of 17q12, though rare, elevates the risk of epilepsy and mental retardation.

CASE PRESENTATION: This study focuses on a 33-year-old woman (gravida 1, para 0) who underwent amniocentesis at 22 weeks gestation due to bilateral hyperechogenic kidneys observed on prenatal ultrasound.

RESULTS

Chromosomal microarray analysis (CMA) unveiled a 1.46-Mb microdeletion on chromosome 17q12 in the fetus, spanning positions 35,802,057 to 37,261,945 (hg19). Trio whole-exome sequencing (WES) revealed 17q12 microdeletion in the fetus and 17q12 microduplication in the father. Notably, at the 3-year follow-up, the baby exhibited a normal phenotype.

CONCLUSIONS

This research provides a comprehensive description of the phenotype in a rare family featuring 17q12 microdeletion and microduplication. Employing a combination of karyotype analysis, CMA, WES, prenatal ultrasound, and genetic counseling proves helpful in the prenatal diagnosis of chromosomal microdeletions/microduplications.