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Li JW, Qian YJ, Mao SJ, Chao YQ, Qin YF, Hu CX, Li ZL, Zou CC. Clinical features associated with maternal uniparental disomy for chromosome 6. Mol Cytogenet 2024; 17:18. [PMID: 39075593 PMCID: PMC11287833 DOI: 10.1186/s13039-024-00688-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 07/20/2024] [Indexed: 07/31/2024] Open
Abstract
BACKGROUND Maternal uniparental disomy for chromosome 6 (upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat) has been previously reported to cause intrauterine growth restriction (IUGR), but the specific clinical phenotype has not been defined. Based on clinical data from two new cases and patients from the literature, specific phenotypes and mechanisms will be discussed further. CASE PRESENTATION In case 1, a maternal isodisomy mixed with a heterodisomy was found on chromosome 6, including a regional absence of heterozygosity between 6q23.3 and 6q27. In case 2, a homozygous SCUBE3 mutation and upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat, involving the 6p21.1-25.1 region were found. Clinical data related to upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat were also reviewed. Of all the 21 reported cases with upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat (including our 2 cases), 18 (85.7%) presented IUGR. CONCLUSIONS The phenotypes of the two newly identified patients with upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat further suggest that IUGR is associated with upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat and case 2 is the first reported upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat patient with a homozygous SCUBE3 gene mutation. However, the specific phenotypes involved in upd(Cajaiba MM, Witchel S, Madan-Khetarpal S, Hoover J, Hoffner L, Macpherson T, et al. Prenatal diagnosis of trisomy 6 rescue resulting in paternal UPD6 with novel placental findings. Am J Med Genet Part A. 2011;155 A(8):1996-2002.)mat and the related mechanisms need to be further studied.
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Affiliation(s)
- Jing-Wen Li
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
| | - Yan-Jie Qian
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
| | - Shao-Jia Mao
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
| | - Yun-Qi Chao
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
| | - Yi-Fang Qin
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
| | - Chen-Xi Hu
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
| | - Zheng-Lan Li
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China
- Department of Pediatrics, the Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, 215008, China
| | - Chao-Chun Zou
- Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, No 3333 Binsheng Road, Hangzhou, 310052, China.
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Jiang Y, Xiao YX, Xiong JJ, Zhang VW, Dong C, Xu L, Liu F. Maternal uniparental disomy for chromosome 6 in 2 prenatal cases with IUGR: case report and literature review. Mol Cytogenet 2024; 17:1. [PMID: 38173004 PMCID: PMC10765649 DOI: 10.1186/s13039-023-00670-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Uniparental disomy (UPD) is a rare genetic condition leading to potential disease risks. Maternal UPD of chromosome 6 upd(6)mat is exceptionally rare, with limited cases reported. This study reported two new cases of upd(6)mat and reviewed the literature of previous cases. CASE PRESENTATION Both cases exhibited intrauterine growth restriction (IUGR), and genetic analysis confirmed upd(6)mat in each case. The literature review identified a total of 19 cases. IUGR and preterm labor were the most common two symptoms observed, and additional anomalies and genetic variations were also reported in some cases. CONCLUSION upd(6)mat is potentially associatied with IUGR, but the precise genotype-phenotype relationship remains unclear. The cases with upd(6)mat may present clinical features due to imprinting disorders.
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Affiliation(s)
- Yan Jiang
- Chongqing Health Center for Women and Children/Women and Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Yang Xue Xiao
- Chongqing Health Center for Women and Children/Women and Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Jiao Jiao Xiong
- Chongqing Health Center for Women and Children/Women and Children's Hospital of Chongqing Medical University, Chongqing, China
| | | | | | - Lei Xu
- AmCare Genomics Lab, Guangzhou, China
| | - Fang Liu
- Chongqing Health Center for Women and Children/Women and Children's Hospital of Chongqing Medical University, Chongqing, China.
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Spiegel R, Schwahn BC, Squires L, Confer N. Molybdenum cofactor deficiency: A natural history. J Inherit Metab Dis 2022; 45:456-469. [PMID: 35192225 PMCID: PMC9313850 DOI: 10.1002/jimd.12488] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 11/09/2022]
Abstract
Molybdenum cofactor deficiency (MoCD) includes three ultrarare autosomal recessive inborn errors of metabolism (MoCD type A [MoCD-A], MoCD-B, and MoCD-C) that cause sulfite intoxication disorders. This natural history study analyzed retrospective data for 58 living or deceased patients (MoCD-A, n = 41; MoCD-B, n = 17). MoCD genotype, survival, neuroimaging, and medical history were assessed retrospectively. Prospective biomarker data were collected for 21 living MoCD patients. The primary endpoint was survival to 1 year of age in MoCD-A patients. Of the 58 MoCD patients, 49 (MoCD-A, n = 36; MoCD-B, n = 13) had first presenting symptoms by Day 28 (neonatal onset; median: 2 and 4 days, respectively). One-year survival rates were 77.4% (overall), 71.8% (neonatal onset MoCD-A), and 76.9% (neonatal onset MoCD-B); median ages at death were 2.4, 2.4, and 2.2 years, respectively. The most common presenting symptoms in the overall population were seizures (60.3%) and feeding difficulties (53.4%). Sequelae included profound developmental delay, truncal hypotonia, limb hypertonia that evolved to spastic quadriplegia or diplegia, dysmorphic features, and acquired microcephaly. In MoCD-A and MoCD-B, plasma and urinary xanthine and S-sulfocysteine concentrations were high; urate remained below the normal reference range. MOCS1 mutation homozygosity was common. Six novel mutations were identified. MoCD is a severe neurodegenerative disorder that often manifests during the neonatal period with intractable seizures and feeding difficulties, with rapidly progressive significant neurologic disabilities and high 1-year mortality rates. Delineation of MoCD natural history supports evaluations of emerging replacement therapy with cPMP for MoCD-A, which may modify disease course for affected individuals.
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Affiliation(s)
- Ronen Spiegel
- Emek Medical CenterAfulaIsrael
- Rappaport school of MedicineTechnionHaifaIsrael
| | - Bernd C. Schwahn
- Manchester Centre for Genomic Medicine, St Mary's HospitalManchester University NHS Foundation Trust, Health Innovation ManchesterManchesterUK
- Division of Evolution & Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
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4
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Hinderhofer K, Mechler K, Hoffmann GF, Lampert A, Mountford WK, Ries M. Critical appraisal of genotype assessment in molybdenum cofactor deficiency. J Inherit Metab Dis 2017; 40:801-811. [PMID: 28900816 DOI: 10.1007/s10545-017-0077-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 07/10/2017] [Accepted: 07/21/2017] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Molybdenum cofactor deficiency (MoCD) is an ultra-orphan, life-threatening disease. Substrate substitution therapy has successfully been performed in single cases of MoCD type A and clinical trials are underway for drug registration. We present an innovative approach for classification of genotype severity to test the hypothesis that milder sequence variants in MoCD result in a less severe disease phenotype quantitated by patient survival. METHODS All available worldwide published cases with clinical and genetic data were included (n = 40). We stratified the already published disease causing sequence variants as mild or severe with the use of in silico prediction programs, where possible and assessed the possible impact of the variants on the expression of the gene or function of the expressed protein. In a compound heterozygous situation the mildest sequence variant determined the genotype. Subsequently, clinical manifestations and outcomes of both groups were compared. RESULTS Patients with a severe genotype showed a median survival of 15 months and had a lower probability of survival compared to patients with mild genotypes who were all alive at last reported follow-up (p = 0.0203, Log-rank test). DISCUSSION The severity of the genotype assessed by in silico prediction and further classification explained survival in molybdenum cofactor deficiency and may therefore be considered a confounder for the outcome of therapeutic clinical trials requiring adjustment in the clinical trial design or analysis. These results should further be investigated by future in vitro or in vivo functional studies. Caution should be taken with this approach for the classification of variants in molecular genetic diagnostics or genetic counseling.
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Affiliation(s)
| | - Konstantin Mechler
- Pediatric Psychopharmacology, Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, J 5, 68159, Mannheim, Germany.
| | - Georg F Hoffmann
- Pediatric Neurology and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, and Center for Rare Disorders, Heidelberg University Hospital, Heidelberg, Germany
| | - Anette Lampert
- Department of Clinical Pharmacology and Pharmacoepidemiology, Heidelberg University Hospital, Heidelberg, Germany
- Cooperation Unit Clinical Pharmacy, Heidelberg University Hospital, Heidelberg, Germany
| | - William K Mountford
- University of North Carolina Wilmington, Wilmington, NC, USA
- Quintiles Inc., Smyrna, GA, USA
| | - Markus Ries
- Pediatric Neurology and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, and Center for Rare Disorders, Heidelberg University Hospital, Heidelberg, Germany
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Eggermann T, Oehl-Jaschkowitz B, Dicks S, Thomas W, Kanber D, Albrecht B, Begemann M, Kurth I, Beygo J, Buiting K. The maternal uniparental disomy of chromosome 6 (upd(6)mat) "phenotype": result of placental trisomy 6 mosaicism? Mol Genet Genomic Med 2017; 5:668-677. [PMID: 29178649 PMCID: PMC5702562 DOI: 10.1002/mgg3.324] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/28/2017] [Accepted: 07/05/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Maternal uniparental disomy of chromosome 6 (upd(6)mat) is a rare finding and its clinical relevance is currently unclear. Based on clinical data from two new cases and patients from the literature, the pathogenetic significance of upd(6)mat is delineated. METHODS Own cases were molecularly characterized for isodisomic uniparental regions on chromosome 6. For further cases with upd(6)mat, a literature search was conducted and genetic and clinical data were ascertained. RESULTS Comparison of isodisomic regions between the new upd(6)mat cases and those from four reports did not reveal any common isodisomic region. Among the patients with available cytogenetic data, five had a normal karyotype in lymphocytes, whereas a trisomy 6 (mosaicism) was detected prenatally in four cases. A common clinical picture was not obvious in upd(6)mat, but intrauterine growth restriction (IUGR) and preterm delivery were frequent. CONCLUSION A common upd(6)mat phenotype is not obvious, but placental dysfunction due to trisomy 6 mosaicism probably contributes to IUGR and preterm delivery. In fact, other clinical features observed in upd(6)mat patients might be caused by homozygosity of recessive mutations or by an undetected trisomy 6 cell line. Upd(6)mat itself is not associated with clinical features, and can rather be regarded as a biomarker. In case upd(6)mat is detected, the cause for the phenotype is identified indirectly, but the UPD is not the basic cause.
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Affiliation(s)
- Thomas Eggermann
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | | | - Severin Dicks
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | | | - Deniz Kanber
- Institute of Human Genetics, University of Essen, Essen, Germany
| | - Beate Albrecht
- Institute of Human Genetics, University of Essen, Essen, Germany
| | - Matthias Begemann
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Ingo Kurth
- Medical Faculty, Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Jasmin Beygo
- Institute of Human Genetics, University of Essen, Essen, Germany
| | - Karin Buiting
- Institute of Human Genetics, University of Essen, Essen, Germany
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6
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Leung WC, Lau WL, Lo TK, Lau TK, Lam YY, Kan A, Chan K, Lau ET, Tang MH. Two IUGR foetuses with maternal uniparental disomy of chromosome 6 or UPD(6)mat. J OBSTET GYNAECOL 2016; 37:113-115. [PMID: 27922284 DOI: 10.1080/01443615.2016.1242558] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Wing Cheong Leung
- Department of Obstetrics & Gynaecology, Kwong Wah Hospital, Hong Kong Special Administrative Region, China
| | - Wai Lam Lau
- Department of Obstetrics & Gynaecology, Kwong Wah Hospital, Hong Kong Special Administrative Region, China
| | - T. K. Lo
- Department of Obstetrics & Gynaecology, Queen Mary Hospital, Hong Kong Special Administrative Region, China
| | - Tze Kin Lau
- Fetal Medicine Centre, Paramount Medical Centre, Hong Kong Special Administrative Region, China
| | - Y. Y. Lam
- Department of Paediatrics, Kwong Wah Hospital, Hong Kong Special Administrative Region, China
| | - Anita Kan
- Department of Obstetrics & Gynaecology, Queen Mary Hospital, Hong Kong Special Administrative Region, China
| | - Kelvin Chan
- Department of Obstetrics & Gynaecology, Queen Mary Hospital, Hong Kong Special Administrative Region, China
| | - Elizabeth T. Lau
- Department of Obstetrics & Gynaecology, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Mary H. Tang
- Department of Obstetrics & Gynaecology, The University of Hong Kong, Hong Kong Special Administrative Region, China
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7
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Zaki MS, Selim L, El-Bassyouni HT, Issa MY, Mahmoud I, Ismail S, Girgis M, Sadek AA, Gleeson JG, Abdel Hamid MS. Molybdenum cofactor and isolated sulphite oxidase deficiencies: Clinical and molecular spectrum among Egyptian patients. Eur J Paediatr Neurol 2016; 20:714-22. [PMID: 27289259 PMCID: PMC4993451 DOI: 10.1016/j.ejpn.2016.05.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/09/2016] [Accepted: 05/19/2016] [Indexed: 11/17/2022]
Abstract
AIM Molybdenum cofactor deficiency (MoCD) and Sulfite oxidase deficiency (SOD) are rare autosomal recessive conditions of sulfur-containing amino acid metabolism with overlapping clinical features and emerging therapies. The clinical phenotype is indistinguishable and they can only be differentiated biochemically. MOCS1, MOCS2, MOCS3, and GPRN genes contribute to the synthesis of molybdenum cofactor, and SUOX gene encodes sulfite oxidase. The aim of this study was to elucidate the clinical, radiological, biochemical and molecular findings in patients with SOD and MoCD. METHODS Detailed clinical and radiological assessment of 9 cases referred for neonatal encephalopathy with hypotonia, microcephaly, and epilepsy led to a consideration of disorders of sulfur-containing amino acid metabolism. The diagnosis of six with MoCD and three with SOD was confirmed by biochemical tests, targeted sequencing, and whole exome sequencing where suspicion of disease was lower. RESULTS Novel SUOX mutations were detected in 3 SOD cases and a novel MOCS2 mutation in 1 MoCD case. Most patients presented in the first 3 months of life with intractable tonic-clonic seizures, axial hypotonia, limb hypertonia, exaggerated startle response, feeding difficulties, and progressive cystic encephalomalacia on brain imaging. A single patient with MoCD had hypertrophic cardiomyopathy, hitherto unreported with these diseases. INTERPRETATION Our results emphasize that intractable neonatal seizures, spasticity, and feeding difficulties can be important early signs for these disorders. Progressive microcephaly, intellectual disability and specific brain imaging findings in the first year were additional diagnostic aids. These clinical cues can be used to minimize delays in diagnosis, especially since promising treatments are emerging for MoCD type A.
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Affiliation(s)
- Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt.
| | - Laila Selim
- Pediatric Department, Neurometabolic Clinic, Cairo University, Cairo 12613, Egypt
| | - Hala T El-Bassyouni
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt
| | - Mahmoud Y Issa
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt
| | - Iman Mahmoud
- Pediatric Department, Neurometabolic Clinic, Cairo University, Cairo 12613, Egypt
| | - Samira Ismail
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt
| | - Mariane Girgis
- Pediatric Department, Neurometabolic Clinic, Cairo University, Cairo 12613, Egypt
| | - Abdelrahim A Sadek
- Pediatric Neurology Department, Faculty of Medicine, Sohag University, Sohag 82524, Egypt
| | - Joseph G Gleeson
- Laboratory for Pediatric Brain Disease, Howard Hughes Medical Institute, Department of Neurosciences, University of California, San Diego, CA 92093, USA
| | - Mohamed S Abdel Hamid
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt
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8
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Maternal uniparental disomy for chromosome 6 in a patient with IUGR, ambiguous genitalia, and persistent mullerian structures. Am J Med Genet A 2016; 170:3227-3230. [DOI: 10.1002/ajmg.a.37876] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 07/18/2016] [Indexed: 11/07/2022]
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9
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Martin HC, Kim GE, Pagnamenta AT, Murakami Y, Carvill GL, Meyer E, Copley RR, Rimmer A, Barcia G, Fleming MR, Kronengold J, Brown MR, Hudspith KA, Broxholme J, Kanapin A, Cazier JB, Kinoshita T, Nabbout R, Bentley D, McVean G, Heavin S, Zaiwalla Z, McShane T, Mefford HC, Shears D, Stewart H, Kurian MA, Scheffer IE, Blair E, Donnelly P, Kaczmarek LK, Taylor JC. Clinical whole-genome sequencing in severe early-onset epilepsy reveals new genes and improves molecular diagnosis. Hum Mol Genet 2014; 23:3200-11. [PMID: 24463883 PMCID: PMC4030775 DOI: 10.1093/hmg/ddu030] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 01/20/2014] [Indexed: 11/13/2022] Open
Abstract
In severe early-onset epilepsy, precise clinical and molecular genetic diagnosis is complex, as many metabolic and electro-physiological processes have been implicated in disease causation. The clinical phenotypes share many features such as complex seizure types and developmental delay. Molecular diagnosis has historically been confined to sequential testing of candidate genes known to be associated with specific sub-phenotypes, but the diagnostic yield of this approach can be low. We conducted whole-genome sequencing (WGS) on six patients with severe early-onset epilepsy who had previously been refractory to molecular diagnosis, and their parents. Four of these patients had a clinical diagnosis of Ohtahara Syndrome (OS) and two patients had severe non-syndromic early-onset epilepsy (NSEOE). In two OS cases, we found de novo non-synonymous mutations in the genes KCNQ2 and SCN2A. In a third OS case, WGS revealed paternal isodisomy for chromosome 9, leading to identification of the causal homozygous missense variant in KCNT1, which produced a substantial increase in potassium channel current. The fourth OS patient had a recessive mutation in PIGQ that led to exon skipping and defective glycophosphatidyl inositol biosynthesis. The two patients with NSEOE had likely pathogenic de novo mutations in CBL and CSNK1G1, respectively. Mutations in these genes were not found among 500 additional individuals with epilepsy. This work reveals two novel genes for OS, KCNT1 and PIGQ. It also uncovers unexpected genetic mechanisms and emphasizes the power of WGS as a clinical tool for making molecular diagnoses, particularly for highly heterogeneous disorders.
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Affiliation(s)
- Hilary C Martin
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Grace E Kim
- Departments of Cellular and Molecular Physiology and Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | - Alistair T Pagnamenta
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK, NIHR Biomedical Research Centre, Oxford, UK
| | - Yoshiko Murakami
- Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Gemma L Carvill
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA
| | - Esther Meyer
- Neurosciences Unit, UCL-Institute of Child Health, London, UK, Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Richard R Copley
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK, NIHR Biomedical Research Centre, Oxford, UK
| | - Andrew Rimmer
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Giulia Barcia
- Department of Paediatric Neurology, Centre de Reference Epilepsies Rares, Hôpital Necker-Enfants Malades, Paris, France
| | - Matthew R Fleming
- Departments of Cellular and Molecular Physiology and Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | - Jack Kronengold
- Departments of Cellular and Molecular Physiology and Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | - Maile R Brown
- Departments of Cellular and Molecular Physiology and Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | - Karl A Hudspith
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK, NIHR Biomedical Research Centre, Oxford, UK
| | - John Broxholme
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Alexander Kanapin
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | - Taroh Kinoshita
- Department of Immunoregulation, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Rima Nabbout
- Department of Paediatric Neurology, Centre de Reference Epilepsies Rares, Hôpital Necker-Enfants Malades, Paris, France
| | | | - Gil McVean
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Sinéad Heavin
- Departments of Medicine and Paediatrics, Florey Institute, The University of Melbourne, Austin Health and Royal Children's Hospital, Melbourne, VIC, Australia
| | - Zenobia Zaiwalla
- Department of Clinical Neurophysiology, John Radcliffe Hospital, Oxford, UK
| | - Tony McShane
- Department of Paediatrics, Children's Hospital Oxford, John Radcliffe Hospital, Oxford, UK
| | - Heather C Mefford
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA, USA
| | - Deborah Shears
- Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Helen Stewart
- Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Manju A Kurian
- Neurosciences Unit, UCL-Institute of Child Health, London, UK
| | - Ingrid E Scheffer
- Departments of Medicine and Paediatrics, Florey Institute, The University of Melbourne, Austin Health and Royal Children's Hospital, Melbourne, VIC, Australia
| | - Edward Blair
- Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Peter Donnelly
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Leonard K Kaczmarek
- Departments of Cellular and Molecular Physiology and Pharmacology, Yale University School of Medicine, New Haven, CT, USA
| | - Jenny C Taylor
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK, NIHR Biomedical Research Centre, Oxford, UK,
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King JE, Dexter A, Gadi I, Zvereff V, Martin M, Bloom M, Vanderver A, Pizzino A, Schmidt JL. Maternal uniparental isodisomy causing autosomal recessive GM1 gangliosidosis: a clinical report. J Genet Couns 2014; 23:734-41. [PMID: 24777551 DOI: 10.1007/s10897-014-9720-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 03/25/2014] [Indexed: 01/18/2023]
Abstract
Uniparental disomy is a genetic cause of disease that may result in the inheritance of an autosomal recessive condition. A child with developmental delay and hypotonia was seen and found to have severely abnormal myelination. Lysosomal enzyme testing identified an isolated deficiency of beta-galactosidase. Subsequently, homozygous missense mutations in the galactosidase, beta 1 (GLB1) gene on chromosome 3 were found. Parental testing confirmed inheritance of two copies of the same mutated maternal GLB1 gene, and no paternal copy. SNP analysis was also done to confirm paternity. The patient was ultimately diagnosed with autosomal recessive GM1 gangliosidosis caused by maternal uniparental isodisomy. We provide a review of this patient and others in which uniparental disomy (UPD) of a non-imprinted chromosome unexpectedly caused an autosomal recessive condition. This is the first case of GM1 gangliosidosis reported in the literature to have been caused by UPD. It is important for genetic counselors and other health care providers to be aware of the possibility of autosomal recessive disease caused by UPD. UPD as a cause of autosomal recessive disease drastically changes the recurrence risk for families, and discussions surrounding UPD can be complex. Working with families to understand UPD when it occurs requires a secure and trusting counselor-family relationship.
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Affiliation(s)
- Jessica E King
- Department of Neurology, Children's National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010, USA
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Roosing S, van den Born LI, Hoyng CB, Thiadens AAHJ, de Baere E, Collin RWJ, Koenekoop RK, Leroy BP, van Moll-Ramirez N, Venselaar H, Riemslag FCC, Cremers FPM, Klaver CCW, den Hollander AI. Maternal uniparental isodisomy of chromosome 6 reveals a TULP1 mutation as a novel cause of cone dysfunction. Ophthalmology 2013; 120:1239-46. [PMID: 23499059 DOI: 10.1016/j.ophtha.2012.12.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 12/04/2012] [Accepted: 12/04/2012] [Indexed: 11/28/2022] Open
Abstract
PURPOSE The majority of the genetic causes of autosomal recessive (ar) cone dystrophy (CD) and cone-rod dystrophy (CRD) are currently unknown. We used a high-resolution homozygosity mapping approach in a cohort of patients with CD or CRD to identify new genes for ar cone disorders. DESIGN Case series. PARTICIPANTS A cohort of 159 patients with ar CD and 91 patients with CRD. METHODS The genomes of 83 patients with ar CD and 73 patients with CRD were analyzed for homozygous regions using single nucleotide polymorphism (SNP) microarrays. One patient showed homozygosity of SNPs across chromosome 6, and segregation analysis was performed using microsatellite markers. Direct sequencing of all retinal disease genes on chromosome 6 revealed a novel pathogenic TULP1 mutation in this patient. A cohort of 159 individuals with CD and 91 individuals with CRD was screened for this particular mutation using the restriction enzyme HhaI. The medical history of patients carrying the TULP1 mutation was reviewed and additional ophthalmic examinations were performed, including electroretinography (ERG), perimetry, optical coherence tomography (OCT), fundus autofluorescence (FAF), and fundus photography. MAIN OUTCOME MEASURES TULP1 mutations, age at diagnosis, visual acuity, fundus appearance, color vision defects, visual field, ERG, FAF, and OCT findings. RESULTS In 1 patient, homozygosity mapping and subsequent segregation analysis revealed maternal uniparental disomy (UPD) of chromosome 6. A novel homozygous missense mutation (p.Arg420Ser) was identified in TULP1, whereas no mutations were detected in other retinal disease genes on chromosome 6. The mutation affects a highly conserved amino acid residue in the Tubby domain and is predicted to be pathogenic. The same homozygous mutation was also identified in an additional, unrelated patient with CRD. Both patients carrying the p.Arg420Ser mutation presented with a bull's eye maculopathy. The first patient had progressive loss of visual acuity with a relatively preserved ERG, whereas the second patient developed loss of visual acuity, peripheral degeneration, and severely reduced ERG responses in a cone-rod pattern. CONCLUSIONS Maternal UPD of chromosome 6 unmasked a mutation in the TULP1 gene as a novel cause of cone dysfunction. This expands the disease spectrum of TULP1 mutations from Leber congenital amaurosis and early-onset retinitis pigmentosa to cone-dominated disease. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Susanne Roosing
- Department of Human Genetics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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12
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Bayram E, Topcu Y, Karakaya P, Yis U, Cakmakci H, Ichida K, Kurul SH. Molybdenum cofactor deficiency: review of 12 cases (MoCD and review). Eur J Paediatr Neurol 2013; 17:1-6. [PMID: 23122324 DOI: 10.1016/j.ejpn.2012.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/07/2012] [Accepted: 10/13/2012] [Indexed: 11/19/2022]
Abstract
Molybdenum cofactor deficiency is a rare inborn error of metabolism. The major clinical symptoms are intractable neonatal seizures, progressive encephalopathy, facial dysmorphic features and feeding difficulties. Most of the patients are misdiagnosed as hypoxic ischemic encephalopathy. The majority of patients have mutations in the MOCS1 and MOCS2 genes. Although the therapeutic treatment strategies have not been improved, genetic analysis is essential to elucidate the disease. Here, we report a review of 12 patients with Molybdenum cofactor deficiency reported from Turkey.
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Affiliation(s)
- Erhan Bayram
- Dokuz Eylul University Hospital, Department of Pediatrics, Division of Pediatric Neurology, 35340 Balcova, Izmir, Turkey.
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13
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Poke G, Doody M, Prado J, Gattas M. Segmental Maternal UPD6 with Prenatal Growth Restriction. Mol Syndromol 2012; 3:270-3. [PMID: 23599697 DOI: 10.1159/000345168] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2012] [Indexed: 11/19/2022] Open
Abstract
We report a child with segmental maternal uniparental isodisomy of chromosome 6, involving most of the long arm distal to 6q16, detected by SNP microarray. Clinical features include prenatal growth restriction, global developmental delay, and severe gastro-esophageal reflux disease. Maternal uniparental disomy (UPD) of chromosome 6 has previously been reported to cause intrauterine growth restriction. Paternal UPD of this chromosome is well known to cause transient neonatal diabetes mellitus. We discuss reported cases of maternal UPD of chromosome 6 and consider whether our patient's features may be due to disordered imprinting or unmasking of an autosomal recessive condition.
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Affiliation(s)
- G Poke
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Qld., Australia
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Reiss J, Hahnewald R. Molybdenum cofactor deficiency: Mutations in GPHN, MOCS1, and MOCS2. Hum Mutat 2010; 32:10-8. [DOI: 10.1002/humu.21390] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Sasaki K, Okamoto N, Kosaki K, Yorifuji T, Shimokawa O, Mishima H, Yoshiura KI, Harada N. Maternal uniparental isodisomy and heterodisomy on chromosome 6 encompassing a CUL7 gene mutation causing 3M syndrome. Clin Genet 2010; 80:478-83. [DOI: 10.1111/j.1399-0004.2010.01599.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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