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Ravenscroft G, Pannell S, O'Grady G, Ong R, Ee HC, Faiz F, Marns L, Goel H, Kumarasinghe P, Sollis E, Sivadorai P, Wilson M, Magoffin A, Nightingale S, Freckmann ML, Kirk EP, Sachdev R, Lemberg DA, Delatycki MB, Kamm MA, Basnayake C, Lamont PJ, Amor DJ, Jones K, Schilperoort J, Davis MR, Laing NG. Variants in ACTG2 underlie a substantial number of Australasian patients with primary chronic intestinal pseudo-obstruction. Neurogastroenterol Motil 2018; 30:e13371. [PMID: 29781137 DOI: 10.1111/nmo.13371] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/09/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Primary chronic intestinal pseudo-obstruction (CIPO) is a rare, potentially life-threatening disorder characterized by severely impaired gastrointestinal motility. The objective of this study was to examine the contribution of ACTG2, LMOD1, MYH11, and MYLK mutations in an Australasian cohort of patients with a diagnosis of primary CIPO associated with visceral myopathy. METHODS Pediatric and adult patients with primary CIPO and suspected visceral myopathy were recruited from across Australia and New Zealand. Sanger sequencing of the genes encoding enteric gamma-actin (ACTG2) and smooth muscle leiomodin (LMOD1) was performed on DNA from patients, and their relatives, where available. MYH11 and MYLK were screened by next-generation sequencing. KEY RESULTS We identified heterozygous missense variants in ACTG2 in 7 of 17 families (~41%) diagnosed with CIPO and its associated conditions. We also identified a previously unpublished missense mutation (c.443C>T, p.Arg148Leu) in one family. One case presented with megacystis-microcolon-intestinal hypoperistalsis syndrome in utero with subsequent termination of pregnancy at 28 weeks' gestation. All of the substitutions identified occurred at arginine residues. No likely pathogenic variants in LMOD1, MYH11, or MYLK were identified within our cohort. CONCLUSIONS AND INFERENCES ACTG2 mutations represent a significant underlying cause of primary CIPO with visceral myopathy and associated phenotypes in Australasian patients. Thus, ACTG2 sequencing should be considered in cases presenting with hypoperistalsis phenotypes with suspected visceral myopathy. It is likely that variants in other genes encoding enteric smooth muscle contractile proteins will contribute further to the genetic heterogeneity of hypoperistalsis phenotypes.
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Affiliation(s)
- G Ravenscroft
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - S Pannell
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - G O'Grady
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - R Ong
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - H C Ee
- Department of Gastroenterology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
| | - F Faiz
- PathWest Diagnostic Genomics, QE II Medical Centre, Nedlands, WA, Australia
| | - L Marns
- PathWest Diagnostic Genomics, QE II Medical Centre, Nedlands, WA, Australia
| | - H Goel
- Hunter Genetics, Waratah, NSW, Australia
| | - P Kumarasinghe
- Faculty of Medicine and Health Sciences, University of Western Australia, Nedlands, WA, Australia
| | - E Sollis
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - P Sivadorai
- PathWest Diagnostic Genomics, QE II Medical Centre, Nedlands, WA, Australia
| | - M Wilson
- Department of Clinical Genetics, Children's Hospital at Westmead, Sydney, NSW, Australia
| | - A Magoffin
- Department of Gastroenterology, The Children's Hospital at Westmead, Westmead, NSW, Australia
| | - S Nightingale
- Paediatric Gastroenterology, John Hunter Children's Hospital, Newcastle, NSW, Australia
| | - M-L Freckmann
- ACT Genetics, The Canberra Hospital, Woden, ACT, Australia
| | - E P Kirk
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia
| | - R Sachdev
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia
| | - D A Lemberg
- Department of Paediatric Gastroenterology, Sydney Children's Hospital, Women's and Children's Health, University of New South Wales, Randwick, NSW, Australia
| | - M B Delatycki
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Melbourne, Vic., Australia
| | - M A Kamm
- Department of Gastroenterology, St Vincent's Hospital and University of Melbourne, Melbourne, Vic., Australia
| | - C Basnayake
- Department of Gastroenterology, St Vincent's Hospital and University of Melbourne, Melbourne, Vic., Australia
| | - P J Lamont
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - D J Amor
- Murdoch Children's Research Institute, Department of Paediatrics, University of Melbourne, Melbourne, Vic., Australia
| | - K Jones
- Faculty of Medicine and Health Sciences, University of Western Australia, Nedlands, WA, Australia
| | - J Schilperoort
- Faculty of Medicine and Health Sciences, University of Western Australia, Nedlands, WA, Australia
| | - M R Davis
- PathWest Diagnostic Genomics, QE II Medical Centre, Nedlands, WA, Australia
| | - N G Laing
- Harry Perkins Institute of Medical Research, University of Western Australia, Nedlands, WA, Australia.,PathWest Diagnostic Genomics, QE II Medical Centre, Nedlands, WA, Australia
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Sivadorai P, Cherninkova S, Bouwer S, Kamenarova K, Angelicheva D, Seeman P, Hollingsworth K, Mihaylova V, Oscar A, Dimitrova G, Kaneva R, Tournev I, Kalaydjieva L. Genetic heterogeneity and minor CYP1B1 involvement in the molecular basis of primary congenital glaucoma in Gypsies. Clin Genet 2008; 74:82-7. [PMID: 18537981 DOI: 10.1111/j.1399-0004.2008.01024.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Primary congenital glaucoma (PCG) is a genetically heterogeneous disorder of autosomal recessive inheritance, with mutations in the cytochrome P450 1B1 (CYP1B1) gene detected in an average of approximately 50% of cases worldwide. The Roma/Gypsies are considered to be a rare example of a single founder CYP1B1 mutation, E387K (identified in the Slovak Roma), accounting for 100% of disease alleles. Contrary to this concept, unusual genetic heterogeneity was revealed in this study of 21 Gypsy PCG patients from Bulgaria and 715 controls from the general Gypsy population. In our small sample of affected subjects, we identified five different CYP1B1 mutations - four known (E229K, R368H, E387K and R390C) and one novel and potentially pathogenic (F445I), which together accounted for approximately 30% of disease alleles. E387K was rare in both the patient and the control group, indicating that its high frequency in the Slovak Roma is the product of local founder effect not representative of the overall molecular pattern of PCG in the Gypsy population. Data on other Mendelian disorders and on the population genetics of the Gypsies suggest that a true founder mutation is likely to exist and has remained undetected. Our analysis of another candidate gene, MYOC, and the GLC3B and GLC3C loci did not provide support for their involvement. The molecular basis of PCG in the Gypsies is thus unresolved, and diagnostic analyses should be extended beyond the E387K mutation.
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Affiliation(s)
- P Sivadorai
- Laboratory of Molecular Genetics, Western Australian Institute for Medical Research, Centre for Medical Research, The University of Western Australia, Perth, Australia
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