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Patel N, Alkuraya H, Alzahrani SS, Nowailaty SR, Seidahmed MZ, Alhemidan A, Ben-Omran T, Ghazi NG, Al-Aqeel A, Al-Owain M, Alzaidan HI, Faqeih E, Kurdi W, Rahbeeni Z, Ibrahim N, Abdulwahab F, Hashem M, Shaheen R, Abouelhoda M, Monies D, Khan AO, Aldahmesh MA, Alkuraya FS. Mutations in known disease genes account for the majority of autosomal recessive retinal dystrophies. Clin Genet 2018; 94:554-563. [PMID: 30054919 DOI: 10.1111/cge.13426] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023]
Abstract
Retinal dystrophies (RDs) are hereditary blinding eye conditions that are highly variable in their clinical presentation. The remarkable genetic heterogeneity that characterizes RD was a major challenge in establishing the molecular diagnosis in these patients until the recent advent of next-generation sequencing. It remains unclear, however, what percentage of autosomal recessive RD remain undiagnosed when all established RD genes are sequenced. We enrolled 75 families in which RD segregates in an apparently autosomal recessive manner. We show that the yield of a multigene panel that contains known RD genes is 67.5%. The higher yield (82.3%) when whole exome sequencing was implemented instead was often due to hits in genes that were not included in the original design of the panel. We also show the value of homozygosity mapping even during the era of exome sequencing in uncovering cryptic mutations. In total, we describe 45 unique likely deleterious variants (of which 18 are novel including one deep intronic and one genomic deletion mutation). Our study suggests that the genetic heterogeneity of autosomal recessive RD is approaching saturation and that any new RD genes will probably account for only a minor role in the mutation burden.
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Affiliation(s)
- N Patel
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H Alkuraya
- Global Eye Care, Specialized Medical Center Hospital, Riyadh, Saudi Arabia
| | - S S Alzahrani
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - S R Nowailaty
- Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - M Z Seidahmed
- Pediatric Department, Security Forces Hospital, Riyadh, Saudi Arabia
| | - A Alhemidan
- Department of Ophthalmology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - T Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - N G Ghazi
- Department of Ophthalmology, Lebanese American University, Lebanese American University Medical Center Rizk Hospital, Beirut, Lebanon
| | - A Al-Aqeel
- Department of Pediatric, Prince Sultan Medical Military City, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - M Al-Owain
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - H I Alzaidan
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - E Faqeih
- Section of Medical Genetics, Department of Pediatric Subspecialties, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - W Kurdi
- Department of Obstetrics and Gynecology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Z Rahbeeni
- Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - N Ibrahim
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - F Abdulwahab
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Hashem
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - R Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - M Abouelhoda
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - D Monies
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
| | - A O Khan
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western University, Cleveland, Ohio
| | - M A Aldahmesh
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.,Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Saudi Human Genome Project, King Abdulaziz City for Science and Technology, Riyadh, Saudi Arabia
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Shaheen R, Al-Dirbashi OY, Al-Hassnan ZN, Al-Owain M, Makhsheed N, Basheeri F, Seidahmed MZ, Salih MAM, Faqih E, Zaidan H, Al-Sayed M, Rahbeeni Z, Al-Sheddi T, Hashem M, Kurdi W, Shimozawa N, Alkuraya FS. Clinical, biochemical and molecular characterization of peroxisomal diseases in Arabs. Clin Genet 2011; 79:60-70. [PMID: 20681997 DOI: 10.1111/j.1399-0004.2010.01498.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peroxisomes are single membrane-bound cellular organelles that carry out critical metabolic reactions perturbation of which leads to an array of clinical phenotypes known as peroxisomal disorders (PD). In this study, the largest of its kind in the Middle East, we sought to comprehensively characterize these rare disorders at the clinical, biochemical and molecular levels. Over a 2-year period, we have enrolled 17 patients representing 16 Arab families. Zellweger-spectrum phenotype was observed in 12 patients and the remaining 5 had the rhizomelic chondrodysplasia punctata phenotype. We show that homozygosity mapping is a cost-effective strategy that enabled the identification of the underlying genetic defect in 100% of the cases. The pathogenic nature of the mutations identified was confirmed by immunofluorescence and complementation assays. We confirm the genetic heterogeneity of PD in our population, expand the pool of pathogenic alleles and draw some phenotype/genotype correlations.
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Affiliation(s)
- R Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
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Seidahmed MZ, Alyamani EA, Rashed MS, Saadallah AA, Abdelbasit OB, Shaheed MM, Rasheed A, Hamid FA, Sabry MA. Total truncation of the molybdopterin/dimerization domains of SUOX protein in an Arab family with isolated sulfite oxidase deficiency. Am J Med Genet A 2005; 136:205-9. [PMID: 15952210 DOI: 10.1002/ajmg.a.30796] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We ascertained a patient with the full-blown phenotype of isolated sulfite oxidase deficiency in a consanguineous Arab family. The proband's phenotype included the presence of intractable seizures in the neonatal period, some dysmorphic features, neuroradiologic findings reminiscent of hypoxic ischemic encephalopathy and rapidly progressive brain destruction leading to severe neurodevelopmental impairment. Biochemically, the patient excreted a large amount of S-sulfocysteine with normal amounts of xanthene and hypoxanthine and had normal plasma uric acid, which was consistent with isolated sulfite oxidase deficiency. We report the identification of the first Arab mutation in SUOX, the gene for sulfite oxidase enzyme, in the ascertained family. The newly identified Arab mutation in the SUOX gene (a single nucleotide deletion, del G1244) is predicted to cause a frame shift at amino acid 117 of the translated protein with the generation of a stop codon and total truncation of the molybdo-pterin- and the dimerizing-domain(s) of SUOX protein expressed from the mutant allele. The identification of this new Arab SUOX mutation should facilitate pre-implantation genetic diagnosis and selection of unaffected embryos for future pregnancy in the ascertained family with the mutation and related families with the same mutation.
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Affiliation(s)
- M Z Seidahmed
- Neonatal Section, Security Forces Hospital, Riyadh, Saudi Arabia
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Miqdad AM, Abdelbasit OB, Shaheed MM, Seidahmed MZ, Abomelha AM, Arcala OP. Intravenous immunoglobulin G (IVIG) therapy for significant hyperbilirubinemia in ABO hemolytic disease of the newborn. J Matern Fetal Neonatal Med 2005; 16:163-6. [PMID: 15590442 DOI: 10.1080/14767050400009873] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Although intravenous immunoglobulin G (IVIG) therapy has been reported in hyperbilirubinemia of Rh hemolytic disease, its use in ABO hemolytic disease has been reported in only a few studies. In our institute we have observed that almost 30% of babies with hyperbilirubinemia due to ABO hemolytic disease required exchange transfusion. OBJECTIVE To determine whether administration of IVIG to newborns with significant hyperbilirubinemia due to ABO hemolytic disease would reduce the need for exchange transfusion as a primary goal in these babies. DESIGN This was a prospective study involving all newborns with significant hyperbilirubinemia due to direct Coombs-positive ABO hemolytic disease. METHODS All healthy term babies with ABO hemolytic disease with positive direct Coombs test in the period between 2000 and 2002 were identified. Significant hyperbilirubinemia was defined as hyperbilirubinemia requiring phototherapy and/or rising by 8.5 micromol/l per h (0.5 mg/dl per h) or more to require exchange transfusion. Babies were randomly assigned into two groups: group 1 (study group) received phototherapy plus IVIG (500 mg/kg); and group 2 (control group) received phototherapy alone. Exchange transfusion was carried out in any group if at any time the bilirubin level reached 340 micromol/l (20 mg/dl) or more, or rose by 8.5 micromol/l per h (0.5 mg/dl per h) in group 2. RESULTS A total of 112 babies were enrolled over 2 years, 56 in each group. Exchange transfusion was carried out in four babies in the study group, while 16 babies in the control group required exchange. Late anemia was not of concern in either group. No adverse effects related to IVIG administration were recorded. CONCLUSION Administration of IVIG to newborns with significant hyperbilirubinemia due to ABO hemolytic disease with positive direct Coomb's test reduces the need for exchange transfusion without producing immediate adverse effects.
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Affiliation(s)
- A M Miqdad
- Department of Pediatrics, Security Forces Hospital, Riyadh, Saudi Arabia
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Abstract
We describe a girl with physical anomalies, accelerated skeletal maturation, failure to thrive, and respiratory difficulties consistent with a diagnosis of Marshall-Smith syndrome (MSS). Chromosome analysis showed an inverted duplication of chromosome 2 [46,XX,inv dup(2)(q37q32) de novo] identified by G banding and confirmed by FISH. Several cases of trisomy 2q3 have been reported and established a syndrome, but the present case is the first to be associated with accelerated skeletal maturation and a clinical picture resembling MSS. This raises the possibility that the cause of MSS involves the q3 region of chromosome 2. Few reports of MSS include study of the karyotype, although the chromosomes were apparently normal in those cases where they have been examined. We suggest that karyotyping be undertaken with particular attention to the 2q3 region in patients with suspected MSS. It also would be prudent to assess bone age in all children with trisomy 2q.
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Affiliation(s)
- M Z Seidahmed
- Department of Pediatrics, Security Forces Hospital, Riyadh, Saudi Arabia
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Seidahmed MZ, Sunada Y, Ozo CO, Hamid F, Campbell KP, Salih MA. Lethal congenital muscular dystrophy in two sibs with arthrogryposis multiplex: new entity or variant of cobblestone lissencephaly syndrome? Neuropediatrics 1996; 27:305-10. [PMID: 9050048 DOI: 10.1055/s-2007-973799] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report on two sisters of first degree cousin parents who were born with severe hypotonia, arthrogryposis multiplex congenita (AMC) and dysmorphic features consistent with the fetal akinesia/hypokinesia sequence. They needed assisted ventilation and each died at the age of 5 months. Both had type II lissencephaly (cobblestone lissencephaly) which was visualized by magnetic resonance imaging (MRI) in the proband. Ophthalmic evaluation revealed no ocular malformations in either of them. Brain auditory evoked potentials (BAEP) revealed bilateral severe sensorineural hearing loss in the proband, whereas an MRI-guided open muscle biopsy of the sartorius muscle (the only remaining thigh muscle) showed features of muscular dystrophy. Immunohistochemistry revealed normal dystrophin, dystrophin-associated glycoproteins (DAG) and merosin. Certain clinical and pathological features distinguish the disease seen in these sisters from reported isolated cases where lethal AMC was associated with brain dysplasia and from the main syndromes of congenital muscular dystrophy/cobblestone lissencephaly. Differences from the Walker-Warburg syndrome, which simulates it in severity, included the absence of severe hydrocephalus, normal creatine kinase (for age) and minimal (mainly periventricular) white matter abnormalities. The findings suggest either an independent entity, in the studied family, or an allelic variation of the cobblestone lissencephaly (type II lissencephaly) syndrome.
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Affiliation(s)
- M Z Seidahmed
- Department of Pediatrics, Security Forces Hospital, Riyadh
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