Prenatal diagnosis and molecular cytogenetic characterization of a de novo interstitial duplication of 14q (14q31.3→q32.12) associated with abnormal maternal serum biochemistry

OBJECTIVE: To present prenatal diagnosis and molecular cytogenetic characterization of a de novo interstitial duplication of 14q (14q31.3→q32.12) in a pregnancy associated with abnormal maternal serum biochemistry. CASE REPORT: A 19-year-old woman underwent amniocentesis in the second trimester because of abnormal maternal serum biochemistry. Her husband was 33 years old. At 16 weeks of gestation, the levels of α-fetoprotein, unconjugated estriol, total β-human chorionic gonadotropin, and inhibin A were 0.8 multiples of median (MoM), 0.84 MoM, 3.06 MoM, and 1.14 MoM, respectively, consistent with a positive trisomy 21 risk of 1/269. Results of an amniocentesis revealed a small de novo interstitial duplication of 14q encompassing 14q31-q32.1. An array comparative genomic hybridization analysis detected a 6.6-Mb duplication at chromosome 14q31.3-q32.12. Results of a fluorescence in situ hybridization analysis showed a direct duplication of interstitial 14q. The karyotype was 46,XY,dup(14) (q31.3q32.12). Level II ultrasound was unremarkable. The parents decided to continue the pregnancy. A 3805-g healthy male baby was delivered at 39 weeks of gestation. When examined at 6 months of age, the neonate was normal in growth and psychomotor development with no apparent phenotypic abnormalities, although long-term follow-ups are required. CONCLUSION: Abnormal maternal serum biochemistry in the second trimester may be a distinctive prenatal feature in pregnancy associated with fetal chromosome 14q duplication.