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Zhang K, Liu S, Gu W, Lv Y, Yu H, Gao M, Wang D, Zhao J, Li X, Gai Z, Zhao S, Liu Y, Yuan Y. Transmission of a Novel Imprinting Center Deletion Associated With Prader-Willi Syndrome Through Three Generations of a Chinese Family: Case Presentation, Differential Diagnosis, and a Lesson Worth Thinking About. Front Genet 2021; 12:630650. [PMID: 34504512 PMCID: PMC8421676 DOI: 10.3389/fgene.2021.630650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/19/2021] [Indexed: 12/02/2022] Open
Abstract
Prader-Willi syndrome (PWS) is a complex genetic syndrome caused by the loss of function of genes in 15q11-q13 that are subject to regulation by genomic imprinting and expressed from the paternal allele only. The main clinical features of PWS patients are hypotonia during the neonatal and infantile stages, accompanied by delayed neuropsychomotor development, hyperphagia, obesity, hypogonadism, short stature, small hands and feet, mental disabilities, and behavioral problems. However, PWS has a clinical overlap with other disorders, especially those with other gene variations or chromosomal imbalances but sharing part of the similar clinical manifestations with PWS, which are sometimes referred to as Prader-Willi syndrome-like (PWS-like) disorders. Furthermore, it is worth mentioning that significant obesity as a consequence of hyperphagia in PWS usually develops between the ages of 1 and 6 years, which makes early diagnosis difficult. Thus, PWS is often not clinically recognized in infants and, on the other hand, may be wrongly suspected in obese and intellectually disabled patients. Therefore, an accurate investigation is necessary to differentiate classical PWS from PWS-like phenotypes, which is imperative for further treatment. For PWS, it is usually sporadic, and very rare family history and affected siblings have been described. Here, we report the clinical and molecular findings in a three-generation family with a novel 550-kb microdeletion affecting the chromosome 15 imprinting center (IC). Overall, the present study finds that the symptoms of our patient are somewhat different from those of typical PWS cases diagnosed and given treatment in our hospital. The familial occurrence and clinical features were challenging to our diagnostic strategy. The microdeletion included a region within the complex small nuclear ribonucleoprotein polypeptide protein N (SNRPN) gene locus encompassing the PWS IC and was identified by using a variety of techniques. Haplotype studies suggest that the IC microdeletion was vertically transmitted from an unaffected paternal grandmother to an unaffected father and then caused PWS in two sibling grandchildren when the IC microdeletion was inherited paternally. Based on the results of our study, preimplantation genetic diagnosis (PGD) was applied successfully to exclude imprinting deficiency in preimplantation embryos before transfer into the mother's uterus. Our study may be especially instructive regarding accurate diagnosis, differential diagnosis, genetic counseling, and PGD for familial PWS patients.
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Affiliation(s)
- Kaihui Zhang
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University, Shanghai, China
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
| | - Shu Liu
- Children Inherited Metabolism and Endocrine Department, Guangdong Women and Children Hospital, Guangzhou, China
| | - Wenjun Gu
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
| | - Yuqiang Lv
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Haihua Yu
- Neonatal Intensive Care Unit, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Min Gao
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Dong Wang
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Jianyuan Zhao
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
| | - Xiaoying Li
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Zhongtao Gai
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Shimin Zhao
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University, Shanghai, China
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
- Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics and Development, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Yi Liu
- Pediatric Research Institute, Qilu Children’s Hospital of Shandong University, Jinan, China
| | - Yiyuan Yuan
- Obstetrics and Gynecology Hospital of Fudan University, Fudan University, Shanghai, China
- State Key Laboratory of Genetic Engineering and School of Life Sciences, Fudan University, Shanghai, China
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Cheon CK. Genetics of Prader-Willi syndrome and Prader-Will-Like syndrome. Ann Pediatr Endocrinol Metab 2016; 21:126-135. [PMID: 27777904 PMCID: PMC5073158 DOI: 10.6065/apem.2016.21.3.126] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 11/29/2022] Open
Abstract
The Prader-Willi syndrome (PWS) is a human imprinting disorder resulting from genomic alterations that inactivate imprinted, paternally expressed genes in human chromosome region 15q11-q13. This genetic condition appears to be a contiguous gene syndrome caused by the loss of at least 2 of a number of genes expressed exclusively from the paternal allele, including SNRPN, MKRN3, MAGEL2, NDN and several snoRNAs, but it is not yet well known which specific genes in this region are associated with this syndrome. Prader-Will-Like syndrome (PWLS) share features of the PWS phenotype and the gene functions disrupted in PWLS are likely to lie in genetic pathways that are important for the development of PWS phenotype. However, the genetic basis of these rare disorders differs and the absence of a correct diagnosis may worsen the prognosis of these individuals due to the endocrine-metabolic malfunctioning associated with the PWS. Therefore, clinicians face a challenge in determining when to request the specific molecular test used to identify patients with classical PWS because the signs and symptoms of PWS are common to other syndromes such as PWLS. This review aims to provide an overview of current knowledge relating to the genetics of PWS and PWLS, with an emphasis on identification of patients that may benefit from further investigation and genetic screening.
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Affiliation(s)
- Chong Kun Cheon
- Division of Pediatric Endocrinology and Metabolism, Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University School of Medicine, Yangsan, Korea
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Dasouki MJ, Youngs EL, Hovanes K. Structural Chromosome Abnormalities Associated with Obesity: Report of Four New subjects and Review of Literature. Curr Genomics 2011; 12:190-203. [PMID: 22043167 PMCID: PMC3137004 DOI: 10.2174/138920211795677930] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 03/29/2011] [Accepted: 03/30/2011] [Indexed: 11/22/2022] Open
Abstract
Obesity in humans is a complex polygenic trait with high inter-individual heritability estimated at 40-70%. Candidate gene, DNA linkage and genome-wide association studies (GWAS) have allowed for the identification of a large set of genes and genomic regions associated with obesity. Structural chromosome abnormalities usually result in congenital anomalies, growth retardation and developmental delay. Occasionally, they are associated with hyperphagia and obesity rather than growth delay. We report four new individuals with structural chromosome abnormalities involving 10q22.3-23.2, 16p11.2 and Xq27.1-q28 chromosomal regions with early childhood obesity and developmental delay. We also searched and summarized the literature for structural chromosome abnormalities reported in association with childhood obesity.
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Affiliation(s)
- Majed J Dasouki
- Departments of Pediatrics and Internal Medicine, Kansas University Medical Center, Kansas City, Kansas, USA
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