Identification of 1p36 deletion syndrome in patients with facial dysmorphism and developmental delay

PURPOSE The 1p36 deletion syndrome is a microdeletion syndrome characterized by developmental delays/intellectual disability, craniofacial dysmorphism, and other congenital anomalies. To date, many cases of this syndrome have been reported worldwide. However, cases with this syndrome have not been reported in Korean populations anywhere. This study was performed to report the clinical and molecular characteristics of five Korean patients with the 1p36 deletion syndrome. METHODS The clinical characteristics of the 5 patients were reviewed. Karyotyping and multiplex ligation-dependent probe amplification (MLPA) analyses were performed for genetic diagnoses. RESULTS All 5 patients had typical dysmorphic features including frontal bossing, flat right parietal bone, low-set ears, straight eyebrows, down-slanting palpebral fissure, hypotelorism, flat nasal roots, midface hypoplasia, pointed chins, small lips, and variable degrees of developmental delay. Each patient had multiple and variable anomalies such as a congenital heart defect including ventricular septal defect, atrial septal defect, and patent duct arteriosus, ventriculomegaly, cryptorchism, or hearing loss. Karyotyping revealed the 1p36 deletion in only 1 patient, although it was confirmed in all 5 patients by MLPA analyses. CONCLUSION All the patients had the typical features of 1p36 deletion. These hallmarks can be used to identify other patients with this condition in their early years in order to provide more appropriate care.