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Carvalho LML, Jorge AADL, Bertola DR, Krepischi ACV, Rosenberg C. A Comprehensive Review of Syndromic Forms of Obesity: Genetic Etiology, Clinical Features and Molecular Diagnosis. Curr Obes Rep 2024; 13:313-337. [PMID: 38277088 DOI: 10.1007/s13679-023-00543-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/08/2023] [Indexed: 01/27/2024]
Abstract
Syndromic obesity refers to obesity occurring with additional clinical findings, such as intellectual disability/developmental delay, dysmorphic features, and congenital malformations. PURPOSE OF REVIEW: To present a narrative review regarding the genetic etiology, clinical description, and molecular diagnosis of syndromic obesity, which is a rare condition with high phenotypic variability and genetic heterogeneity. The following syndromes are presented in this review: Prader-Willi, Bardet-Biedl, Pseudohypoparathyroidism, Alström, Smith-Magenis, Cohen, Temple, 1p36 deletion, 16p11.2 microdeletion, Kleefstra, SIM1-related, Börjeson-Forssman-Lehmann, WAGRO, Carpenter, MORM, and MYT1L-related syndromes. RECENT FINDINGS: There are three main groups of mechanisms for syndromic obesity: imprinting, transcriptional activity regulation, and cellular cilia function. For molecular diagnostic, methods of genome-wide investigation should be prioritized over sequencing of panels of syndromic obesity genes. In addition, we present novel syndromic conditions that need further delineation, but evidences suggest they have a higher frequency of obesity. The etiology of syndromic obesity tends to be linked to disrupted neurodevelopment (central) and is associated with a diversity of genes and biological pathways. In the genetic investigation of individuals with syndromic obesity, the possibility that the etiology of the syndromic condition is independent of obesity should be considered. The accurate genetic diagnosis impacts medical management, treatment, and prognosis, and allows proper genetic counseling.
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Affiliation(s)
- Laura Machado Lara Carvalho
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Laboratory of Human Genetics - LGH, Institute of Biosciences, University of São Paulo (USP), Matão Street 277 - Room 350, São Paulo, SP, Brazil
| | - Alexander Augusto de Lima Jorge
- Genetic Endocrinology Unit, Cellular and Molecular Endocrinology Laboratory (LIM/25), Faculty of Medicine, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Débora Romeo Bertola
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Laboratory of Human Genetics - LGH, Institute of Biosciences, University of São Paulo (USP), Matão Street 277 - Room 350, São Paulo, SP, Brazil
- Genetics Unit of Instituto da Criança, Faculty of Medicine, University of São Paulo (USP), São Paulo, SP, Brazil
| | - Ana Cristina Victorino Krepischi
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Laboratory of Human Genetics - LGH, Institute of Biosciences, University of São Paulo (USP), Matão Street 277 - Room 350, São Paulo, SP, Brazil
| | - Carla Rosenberg
- Human Genome and Stem Cell Research Center, Department of Genetics and Evolutionary Biology, Laboratory of Human Genetics - LGH, Institute of Biosciences, University of São Paulo (USP), Matão Street 277 - Room 350, São Paulo, SP, Brazil.
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Concepción-Zavaleta MJ, Quiroz-Aldave JE, Durand-Vásquez MDC, Gamarra-Osorio ER, Valencia de la Cruz JDC, Barrueto-Callirgos CM, Puelles-León SL, Alvarado-León EDJ, Leiva-Cabrera F, Zavaleta-Gutiérrez FE, Concepción-Urteaga LA, Paz-Ibarra J. A comprehensive review of genetic causes of obesity. World J Pediatr 2024; 20:26-39. [PMID: 37725322 DOI: 10.1007/s12519-023-00757-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 08/16/2023] [Indexed: 09/21/2023]
Abstract
BACKGROUND Obesity is a multifactorial chronic disease with a high, increasing worldwide prevalence. Genetic causes account for 7% of the cases in children with extreme obesity. DATA SOURCES This narrative review was conducted by searching for papers published in the PubMed/MEDLINE, Embase and SciELO databases and included 161 articles. The search used the following search terms: "obesity", "obesity and genetics", "leptin", "Prader-Willi syndrome", and "melanocortins". The types of studies included were systematic reviews, clinical trials, prospective cohort studies, cross-sectional and prospective studies, narrative reviews, and case reports. RESULTS The leptin-melanocortin pathway is primarily responsible for the regulation of appetite and body weight. However, several important aspects of the pathophysiology of obesity remain unknown. Genetic causes of obesity can be grouped into syndromic, monogenic, and polygenic causes and should be assessed in children with extreme obesity before the age of 5 years, hyperphagia, or a family history of extreme obesity. A microarray study, an analysis of the melanocortin type 4 receptor gene mutations and leptin levels should be performed for this purpose. There are three therapeutic levels: lifestyle modifications, pharmacological treatment, and bariatric surgery. CONCLUSIONS Genetic study technologies are in constant development; however, we are still far from having a personalized approach to genetic causes of obesity. A significant proportion of the affected individuals are associated with genetic causes; however, there are still barriers to its approach, as it continues to be underdiagnosed. Video Abstract (MP4 1041807 KB).
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - José Paz-Ibarra
- Department of Medicine, School of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru
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Duis J, Butler MG. Syndromic and Nonsyndromic Obesity: Underlying Genetic Causes in Humans. Adv Biol (Weinh) 2022; 6:e2101154. [PMID: 35680611 DOI: 10.1002/adbi.202101154] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 03/13/2022] [Indexed: 01/28/2023]
Abstract
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.
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Affiliation(s)
- Jessica Duis
- Section of Genetics and Inherited Metabolic Disorders, Children's Hospital Colorado, University of Colorado, Anschutz Medical Campus, 13123 E 16th Ave, Aurora, CO, 80045, USA
| | - Merlin G Butler
- Division of Research and Genetics, Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, 3901 Rainbow Boulevard, MS 4015, Kansas City, KS, 66160, USA
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Mahmoud R, Kimonis V, Butler MG. Genetics of Obesity in Humans: A Clinical Review. Int J Mol Sci 2022; 23:11005. [PMID: 36232301 PMCID: PMC9569701 DOI: 10.3390/ijms231911005] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 11/23/2022] Open
Abstract
Obesity is a complex multifactorial disorder with genetic and environmental factors. There is an increase in the worldwide prevalence of obesity in both developed and developing countries. The development of genome-wide association studies (GWAS) and next-generation sequencing (NGS) has increased the discovery of genetic associations and awareness of monogenic and polygenic causes of obesity. The genetics of obesity could be classified into syndromic and non-syndromic obesity. Prader-Willi, fragile X, Bardet-Biedl, Cohen, and Albright Hereditary Osteodystrophy (AHO) syndromes are examples of syndromic obesity, which are associated with developmental delay and early onset obesity. Non-syndromic obesity could be monogenic, polygenic, or chromosomal in origin. Monogenic obesity is caused by variants of single genes while polygenic obesity includes several genes with the involvement of members of gene families. New advances in genetic testing have led to the identification of obesity-related genes. Leptin (LEP), the leptin receptor (LEPR), proopiomelanocortin (POMC), prohormone convertase 1 (PCSK1), the melanocortin 4 receptor (MC4R), single-minded homolog 1 (SIM1), brain-derived neurotrophic factor (BDNF), and the neurotrophic tyrosine kinase receptor type 2 gene (NTRK2) have been reported as causative genes for obesity. NGS is now in use and emerging as a useful tool to search for candidate genes for obesity in clinical settings.
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Affiliation(s)
- Ranim Mahmoud
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
- Department of Pediatrics, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Virginia Kimonis
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
- Departments of Neurology and Pathology, University of California, Irvine, CA 92697, USA
- Children’s Hospital of Orange County, Orange, CA 92868, USA
| | - Merlin G. Butler
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Tsai HI, Wu Y, Huang R, Su D, Wu Y, Liu X, Wang L, Xu Z, Pang Y, Sun C, He C, Shu F, Zhu H, Wang D, Cheng F, Huang L, Chen H. PHF6 functions as a tumor suppressor by recruiting methyltransferase SUV39H1 to nucleolar region and offers a novel therapeutic target for PHF6-muntant leukemia. Acta Pharm Sin B 2022; 12:1913-1927. [PMID: 35847518 PMCID: PMC9279718 DOI: 10.1016/j.apsb.2021.10.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 09/24/2021] [Accepted: 10/14/2021] [Indexed: 11/22/2022] Open
Abstract
Mutations in the plant homeodomain-like finger protein 6 (PHF6) gene are strongly associated with acute myeloid (AML) and T-cell acute lymphoblastic leukemia (T-ALL). In this study, we demonstrated that PHF6 can bind to H3K9me3 and H3K27me1 on the nucleolar chromatin and recruit histone methyltransferase SUV39H1 to the rDNA locus. The deletion of PHF6 caused a decrease in the recruitment of SUV39H1 to rDNA gene loci, resulting in a reduction in the level of H3K9me3 and the promotion of rDNA transcription. The knockdown of either SUV39H1 or PHF6 significantly attenuated the effects of increase in H3K9me3 and suppressed the transcription of rDNA induced by the overexpression of the other interacting partner, thereby establishing an interdependent relationship between PHF6 and SUV39H1 in their control of rRNA transcription. The PHF6 clinical mutants significantly impaired the ability to bind and recruit SUV39H1 to the rDNA loci, resulting in an increase in rDNA transcription activity, the proliferation of in vitro leukemia cells, and the growth of in vivo mouse xenografts. Importantly, significantly elevated levels of pre-rRNA were observed in clinical AML patients who possessed a mutated version of PHF6. The specific rDNA transcription inhibitor CX5461 significantly reduced the resistance of U937 AML cells deficient in PHF6 to cytarabine, the drug that is most commonly used to treat AML. Collectively, we revealed a novel molecular mechanism by which PHF6 recruits methyltransferase SUV39H1 to the nucleolar region in leukemia and provided a potential therapeutic target for PHF6-mutant leukemia.
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Affiliation(s)
- Hsiang-i Tsai
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
- Department of Medical Imaging, the Affiliated Hospital of Jiangsu University, Zhenjiang 212001, China
| | - Yanping Wu
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Rui Huang
- Department of Hematology, Zhujiang Hospital, Southern Medical University, Guangzhou 510000, China
| | - Dandan Su
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Yingyi Wu
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Xiaoyan Liu
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Linglu Wang
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Zhanxue Xu
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Yuxin Pang
- School of Traditional Medicine Materials Resource, Guangdong Pharmaceutical University, Yunfu 527322, China
| | - Chong Sun
- Immune Regulation in Cancer, German Cancer Research Center, Heidelberg 69120, Germany
| | - Chao He
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Fan Shu
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
| | - Haitao Zhu
- Department of Medical Imaging, the Affiliated Hospital of Jiangsu University, Zhenjiang 212001, China
| | - Dongqing Wang
- Department of Medical Imaging, the Affiliated Hospital of Jiangsu University, Zhenjiang 212001, China
| | - Fang Cheng
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
- Corresponding authors.
| | - Laiqiang Huang
- The Shenzhen Key Lab of Gene and Antibody Therapy, Center for Biotechnology & Biomedicine, Division of Life and Health Sciences, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
- Corresponding authors.
| | - Hongbo Chen
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Shenzhen 518107, China
- Corresponding authors.
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Loss of PHF6 leads to aberrant development of human neuron-like cells. Sci Rep 2020; 10:19030. [PMID: 33149206 PMCID: PMC7642390 DOI: 10.1038/s41598-020-75999-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/22/2020] [Indexed: 11/09/2022] Open
Abstract
Pathogenic variants in PHD finger protein 6 (PHF6) cause Borjeson-Forssman-Lehmann syndrome (BFLS), a rare X-linked neurodevelopmental disorder, which manifests variably in both males and females. To investigate the mechanisms behind overlapping but distinct clinical aspects between genders, we assessed the consequences of individual variants with structural modelling and molecular techniques. We found evidence that de novo variants occurring in females are more severe and result in loss of PHF6, while inherited variants identified in males might be hypomorph or have weaker effects on protein stability. This might contribute to the different phenotypes in male versus female individuals with BFLS. Furthermore, we used CRISPR/Cas9 to induce knockout of PHF6 in SK-N-BE (2) cells which were then differentiated to neuron-like cells in order to model nervous system related consequences of PHF6 loss. Transcriptome analysis revealed a broad deregulation of genes involved in chromatin and transcriptional regulation as well as in axon and neuron development. Subsequently, we could demonstrate that PHF6 is indeed required for proper neuron proliferation, neurite outgrowth and migration. Impairment of these processes might therefore contribute to the neurodevelopmental and cognitive dysfunction in BFLS.
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