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Etiology and Prevalence of Obesity
Published in Claude Bouchard, The Genetics of Obesity, 2020
The cardinal features of Cohen syndrome are hypotonia, truncal obesity, mental retardation, and a characteristic craniofacial appearance, characterized by a high nasal bridge, high arched palate, short philtrum, small jaw, and a characteristic open mouth.16 The obesity is truncal and begins at approximately 5 years of age. Delayed puberty occurs, but there is normal gonadal function or, in some cases, hypogonadotropic hypogonadism. Mental retardation is only mild. This syndrome is probably inherited as an autosomal recessive trait. Friedman and Sack have raised the possibility that it may have a higher prevalence among Ashkenazi Jews.17
Biotechnology and Bioethics
Published in Emmanuel A. Kornyo, A Guide to Bioethics, 2017
It is truism that a tsunami of researchers trouping to vulnerable populations and some think it is just for the curiosity of it akin to tourism. There is generally a renewed interest among researchers to genotype homogenous populations such as the Amish people and some indigenous or Native Americans. This is significant because such genomic data help in comparing other genetic data from other places in order to identify and study population differentiated biomarkers and some genes of interests that might have undergone some evolutionary changes, mutations, or insertions in other heterogeneous populations. These can be clinically significant in developing specific pharmacogenomics interventions. In addition, such homogenous study can and does lead to the identification of some genetic diseases unique to these homogenous groups. For example, some researchers have discovered that mutations in VPS13B gene causes malfunction of the proteins from it leading to Cohen syndrome. But among some Native American tribes, such genetic studies have generated unprecedented controversies. In a seminal work, Tall Bear discusses the socio-historic contexts of the controversies.93 She observed that DNA testing irks and stirs intra-tribal debacles of the purity, identity, and the old scare of colonization and the continual debates of ownership of their “land” and “nations.” Furthermore, some natives feel DNA testing especially postmortem are invasive and disrespectful. As Nick Tipon poignantly notes:These are questions that anyone who gives their genetic material to scientists has to think about. And for Native Americans, who have witnessed their artifacts, remains, and land taken away, shared, and discussed among academics for centuries, concerns about genetic appropriation carry ominous reminders about the past. I might trust this guy, but 100 years from now who is going to get the information? What are people going to do with that information? How can they twist it? Because that's one thing that seems to happen a lot.94
Etiologies of obesity
Published in G. Michael Steelman, Eric C. Westman, Obesity, 2016
To date, there have been several hundred different human obesity cases associated with single gene defects. Some examples include the following (72): Autosomal dominant—achondroplasia, Albright hereditary osteodystrophy, Angelman syndrome, insulin resistance syndromesAutosomal recessive—Alstrom–Hallgren, Cohen, and Fanconi–Bickel syndromesPleiotropic syndromes are clinical syndromes whereby obesity is one of the many constellations of symptoms. There have been approximately 30 of these Mendelian disorders categorized to date, with several of these mutations (if not all) affecting the central or peripheral pathways controlling weight (27).Prader–Willi syndrome—the most common (prevalence 1:25,000) and best characterized human obesity syndrome. Includes progressive obesity, reduced fetal activity, hypotonia at birth, short stature, mental retardation, behavioral abnormalities, hypogonadism, small hands and feet, and hyperphagia usually developing between 12 and 18 months (73).Bardet–Biedl syndrome—also known as Laurence–Moon syndrome (prevalence <1:100,000). Includes polydactyly, developmental delay, impaired vision, hypogonadism, central obesity, and renal abnormalities.Cohen syndrome—dysmorphic features, developmental delay, visual problems, and late childhood or adolescent truncal obesity.Borjeson–Forssman–Lehmann syndrome—mental retardation, obesity, and hypogonadism.Wilson–Turner syndrome—mental retardation, gynecomastia, and childhood onset obesity.
Resolution of cystoid macular edema with topical carbonic anhydrase inhibitor in a patient with retinal dystrophy associated with Cohen syndrome
Published in Ophthalmic Genetics, 2021
Mehmet Orkun Sevik, Aslan Aykut, Özlem Şahin
Cohen Syndrome (CS) is a rare autosomal recessive multisystemic disorder first described in two siblings and an unrelated patient in 1973 by Cohen et al. (1). It is characterized by the variable clinical picture of failure to thrive in infancy, hypotony, microcephaly, characteristic facial appearance, developmental delay, psychomotor retardation, truncal obesity, neutropenia, and ophthalmologic abnormalities; however, clinical diversity of the syndrome has still being established with more than 200 reported cases in the growing literature (2). Genetic testing has a valuable contribution in the diagnosis, and to date, more than 200 variants (with biallelic missense or nonsense mutations) in the vacuolar protein sorting 13 homolog B (VPS13B) gene on chromosome 8q22.2 been reported to cause CS (2,3).
Bilateral angle closure glaucoma in a 28-year-old Cohen syndrome patient
Published in Ophthalmic Genetics, 2018
Ang Li, Alisha Gandhi, Heng Wang, Elias I. Traboulsi
Cohen syndrome is a rare autosomal recessive disease characterized by developmental delay, microcephaly, hypotonia, typical craniofacial features, neutropenia, and ophthalmologic abnormalities (1,2). It is a clinical diagnosis confirmed by identification of pathogenic variants in VPS13B or COH1 on molecular genetic testing. While the most common and consistent finding is one of retinal dystrophy and refractive myopia, case reports have documented variable ophthalmologic manifestations associated with Cohen syndrome, including microspherophakia and anterior segment dysgenesis (3,4). We report a unique case of bilateral acute angle closure in a Cohen syndrome patient that necessitated emergent lensectomy. This case emphasizes the importance of identifying potentially reversible sight threatening ophthalmologic complications in Cohen syndrome.
Novel applications of array comparative genomic hybridization in molecular diagnostics
Published in Expert Review of Molecular Diagnostics, 2018
The second example (Figure 3) illustrates the detection of two multiexonic deletions in trans involving autosomal-recessive-disease gene VPS13B yielding the diagnosis of Cohen syndrome [75]. The patient is an 11-month-old female with clinical features suggestive of Cohen syndrome. CMA revealed two deletions involving one single exon as well as multiple exons in the VPS13B gene (Figure 3a). It is known that a homozygous or compound heterozygous mutations in VPS13B cause of Cohen syndrome [76] and that SNVs, both genomic deletions and duplications, have been found in patients with Cohen syndrome, suggesting that this DNA region is susceptible to genomic rearrangements [77]. After a consultation with the referral physician, parental CMA was performed. It was found that the two intragenic VPS13B CNVs of 130 and 66 kb are in trans, one inherited from each parent. This case indicates that heterozygous multiexonic copy variation in an autosomal-recessive-disease gene should be interpreted in conjunction with the clinical phenotype, and if warranted, phase analysis should be performed before sequence analysis.