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Teke Kisa P, Kose M, Unal O, Er E, Hismi BO, Bulbul FS, Kose E, Gunduz M, Canda E, Kucukcongar A, Arslan N. Clinical and molecular characteristics and time of diagnosis of patients with classical galactosemia in an unscreened population in Turkey. J Pediatr Endocrinol Metab 2019; 32:675-681. [PMID: 31194682 DOI: 10.1515/jpem-2018-0457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/30/2019] [Indexed: 12/23/2022]
Abstract
Classical galactosemia is an autosomal recessive inborn error of metabolism caused by biallelic pathogenic variants in the GALT gene. With the benefit of early diagnosis by newborn screening, the acute presentation of galactosemia can be prevented. In this study, we describe the clinical phenotypes, time of diagnosis and GALT genotypes of 76 galactosemia patients from Turkey, where the disease is not yet included in the newborn screening program. The median age at first symptom was 10 days (range 5-20), while the median age at diagnosis was 30 days (range 17-53). Nearly half of the patients (36 patients, 47.4%) were diagnosed later than age 1 month. Fifty-eight individuals were found to have 18 different pathogenic variants in their 116 mutant alleles. In our sample, Q188R variant has the highest frequency with 53%, the other half of the allele frequency of the patients showed 17 different genotypes. Despite presenting with typical clinical manifestations, classical galactosemia patients are diagnosed late in Turkey. Due to the geographical location of our country, different pathogenic GALT variants may be seen in Turkish patients. In the present study, a clear genotype-phenotype correlation could not be established in patients.
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Affiliation(s)
- Pelin Teke Kisa
- Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Melis Kose
- Division of Pediatric Metabolism and Nutrition, Dr. Behcet Uz Children's Training and Research Hospital, Izmir, Turkey
| | - Ozlem Unal
- Division of Pediatric Metabolism and Nutrition, Ankara Children's Training and Research Hospital, Ankara, Turkey
| | - Esra Er
- Division of Pediatric Metabolism and Nutrition, Ege University Faculty of Medicine, Izmir, Turkey
| | - Burcu Ozturk Hismi
- Division of Pediatric Metabolism and Nutrition, Tepecik Training and Research Hospital, Izmir, Turkey
| | - Fatma Selda Bulbul
- Division of Pediatric Metabolism and Nutrition, Kirikkale University, Kirikkale, Turkey
| | - Engin Kose
- Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Mehmet Gunduz
- Division of Pediatric Metabolism and Nutrition, Ankara Children's Training and Research Hospital, Ankara, Turkey
| | - Ebru Canda
- Division of Pediatric Metabolism and Nutrition, Ege University Faculty of Medicine, Izmir, Turkey
| | - Aynur Kucukcongar
- Division of Pediatric Metabolism and Nutrition, Ankara Children's Training and Research Hospital, Ankara, Turkey
| | - Nur Arslan
- Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
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Management of neonatal cholestasis: Consensus statement of the pediatric gastroenterology chapter of Indian academy of pediatrics. Indian Pediatr 2014; 51:203-10. [DOI: 10.1007/s13312-014-0375-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Tang M, Facchiano A, Rachamadugu R, Calderon F, Mao R, Milanesi L, Marabotti A, Lai K. Correlation assessment among clinical phenotypes, expression analysis and molecular modeling of 14 novel variations in the human galactose-1-phosphate uridylyltransferase gene. Hum Mutat 2012; 33:1107-15. [PMID: 22461411 DOI: 10.1002/humu.22093] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 03/06/2012] [Indexed: 01/20/2023]
Abstract
Galactose-1-phosphate uridylyltransferase (GALT) catalyzes the conversion of galactose-1-phosphate to UDP-galactose, a key step in the galactose metabolism. Deficiency of GALT activity in humans caused by deleterious variations in the GALT gene can cause a potentially lethal disease called classic galactosemia. In this study, we selected 14 novel nucleotide sequence changes in the GALT genes found in galactosemic patients for expression analysis and molecular modeling. Several variants showed decreased levels of expression and decreased abundance in the soluble fraction of the Escherichia coli cell extracts, suggesting altered stability and solubility. Only six variant GALT enzymes had detectable enzymatic activities. Kinetic studies showed that their V(max) decreased significantly. To further characterize the variants at molecular level, we performed static and dynamic molecular modeling studies. Effects of variations on local and/or global structural features of the enzyme were anticipated for the majority of variants. In-depth studies with molecular dynamic simulations on selected variants predicted the alteration of the protein structure even though static models apparently did not highlight any perturbation. Overall, these studies offered new insights on the molecular properties of GALT enzyme, with the aim of correlating them with the clinical outcome. Hum Mutat 33:1107-1115, 2012. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Manshu Tang
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
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