1q21.1 microduplication in a patient with mental impairment and congenital heart defect.

1q21.1 duplication is a rare copy number variant with multiple congenital malformations, including developmental delay, autism spectrum disorder, dysmorphic features and congenital heart anomalies. The present study described a Chinese female patient (age, four years and eight months) with multiple malformations, including congenital heart defect, mental impairment and developmental delay. The parents and the monozygotic twin sister of the patient, however, were physically and psychologically normal. High‑resolution genome‑wide single nucleotide polymorphism array revealed a 1.6‑Mb duplication in chromosome region 1q21.1. This chromosome region contained HFE2, a critical gene involved in hereditary hemochromatosis. However, the parents and monozygotic twin sister of the patient did not carry this genomic lesion. To the best of our knowledge, the present study was the first to report on a 1q21.1 duplication patient in mainland China.