Growth patterns of patients with 1p36 deletion syndrome

Syndromic and Nonsyndromic Obesity: Underlying Genetic Causes in Humans

Growing evidence supports syndromic and nonsyndromic causes of obesity, including genome-wide association studies, candidate gene analysis, advanced genetic technology using next-generation sequencing (NGS), and identification of copy number variants. Identification of susceptibility genes impacts mechanistic understanding and informs precision medicine. The cause of obesity is heterogeneous with complex biological processes playing a role by controlling peptides involved in regulating appetite and food intake, cellular energy, and metabolism. Evidence for heritability shows genetic components contributing to 40%-70% of obesity. Monogenic causes and obesity-related syndromes are discussed and illustrated as well as biological pathways, gene interactions, and factors contributing to the obesity phenotype. Over 550 obesity-related single genes have been identified and summarized in tabular form with approximately 20% of these genes have been added to obesity gene panels for testing by commercially available laboratories. Early studies show that about 10% of patients with severe obesity using NGS testing have a pathogenic gene variant. Discussion to help characterize gene-gene interactions and disease mechanisms for early diagnosis, treatment, and risk factors contributing to disease is incorporated in this review.

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.