Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier
Phenylketonuria (PKU) is an inborn error of metabolism caused by variants in the phenylalanine hydroxylase (PAH) gene and it is characterized by excessively high levels of phenylalanine in body fluids. PKU is a paradigm for a genetic disease that can be treated and majority of developed countries ha...
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| Format: | Article |
| Language: | English |
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Elsevier
2021-12-01
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| Series: | Molecular Genetics and Metabolism Reports |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214426921001178 |
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| author | K. Klaassen M. Djordjevic A. Skakic B. Kecman R. Drmanac S. Pavlovic M. Stojiljkovic |
| author_facet | K. Klaassen M. Djordjevic A. Skakic B. Kecman R. Drmanac S. Pavlovic M. Stojiljkovic |
| author_sort | K. Klaassen |
| collection | DOAJ |
| description | Phenylketonuria (PKU) is an inborn error of metabolism caused by variants in the phenylalanine hydroxylase (PAH) gene and it is characterized by excessively high levels of phenylalanine in body fluids. PKU is a paradigm for a genetic disease that can be treated and majority of developed countries have a population-based newborn screening. Thus, the combination of early diagnosis and immediate initiation of treatment has resulted in normal intelligence for treated PKU patients. Although PKU is a monogenic disease, decades of research and clinical practice have shown that the correlation between the genotype and corresponding phenotype is not simple at all. Attempts have been made to discover modifier genes for PKU cognitive phenotype but without any success so far.We conducted whole genome sequencing of 4 subjects from unrelated non-consanguineous families who presented with pathogenic mutations in the PAH gene, high blood phenylalanine concentrations and near-normal cognitive development despite no treatment. We used cross sample analysis to select genes common for more than one patient. Thus, the SHANK gene family emerged as the only relevant gene family with variants detected in 3 of 4 analyzed patients. We detected two novel variants, p.Pro1591Ala in SHANK1 and p.Asp18Asn in SHANK2, as well as SHANK2:p.Gly46Ser, SHANK2:p.Pro1388_Phe1389insLeuPro and SHANK3:p.Pro1716Thr variants that were previously described. Computational analysis indicated that the identified variants do not abolish the function of SHANK proteins. However, changes in posttranslational modifications of SHANK proteins could influence functioning of the glutamatergic synapses, cytoskeleton regulation and contribute to maintaining optimal synaptic density and number of dendritic spines.Our findings are linking SHANK gene family and brain plasticity in PKU for the first time. We hypothesize that variant SHANK proteins maintain optimal synaptic density and number of dendritic spines under high concentrations of phenylalanine and could have protective modifying effect on cognitive development of PKU patients. |
| first_indexed | 2024-12-17T13:22:49Z |
| format | Article |
| id | doaj.art-d9f96c90fcf040fb8bfc5b302d89122c |
| institution | Directory Open Access Journal |
| issn | 2214-4269 |
| language | English |
| last_indexed | 2024-12-17T13:22:49Z |
| publishDate | 2021-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Molecular Genetics and Metabolism Reports |
| spelling | doaj.art-d9f96c90fcf040fb8bfc5b302d89122c2022-12-21T21:46:50ZengElsevierMolecular Genetics and Metabolism Reports2214-42692021-12-0129100822Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifierK. Klaassen0M. Djordjevic1A. Skakic2B. Kecman3R. Drmanac4S. Pavlovic5M. Stojiljkovic6Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, SerbiaMother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Belgrade, Serbia; School of Medicine, University of Belgrade, Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, SerbiaMother and Child Health Care Institute of Serbia “Dr Vukan Cupic”, Belgrade, SerbiaComplete Genomics Incorporated, San Jose, California 95134, USA; MGI, BGI-Shenzhen, Shenzhen 518083, China; BGI-Shenzhen, Shenzhen 518083, ChinaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, SerbiaInstitute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia; Corresponding author at: Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia.Phenylketonuria (PKU) is an inborn error of metabolism caused by variants in the phenylalanine hydroxylase (PAH) gene and it is characterized by excessively high levels of phenylalanine in body fluids. PKU is a paradigm for a genetic disease that can be treated and majority of developed countries have a population-based newborn screening. Thus, the combination of early diagnosis and immediate initiation of treatment has resulted in normal intelligence for treated PKU patients. Although PKU is a monogenic disease, decades of research and clinical practice have shown that the correlation between the genotype and corresponding phenotype is not simple at all. Attempts have been made to discover modifier genes for PKU cognitive phenotype but without any success so far.We conducted whole genome sequencing of 4 subjects from unrelated non-consanguineous families who presented with pathogenic mutations in the PAH gene, high blood phenylalanine concentrations and near-normal cognitive development despite no treatment. We used cross sample analysis to select genes common for more than one patient. Thus, the SHANK gene family emerged as the only relevant gene family with variants detected in 3 of 4 analyzed patients. We detected two novel variants, p.Pro1591Ala in SHANK1 and p.Asp18Asn in SHANK2, as well as SHANK2:p.Gly46Ser, SHANK2:p.Pro1388_Phe1389insLeuPro and SHANK3:p.Pro1716Thr variants that were previously described. Computational analysis indicated that the identified variants do not abolish the function of SHANK proteins. However, changes in posttranslational modifications of SHANK proteins could influence functioning of the glutamatergic synapses, cytoskeleton regulation and contribute to maintaining optimal synaptic density and number of dendritic spines.Our findings are linking SHANK gene family and brain plasticity in PKU for the first time. We hypothesize that variant SHANK proteins maintain optimal synaptic density and number of dendritic spines under high concentrations of phenylalanine and could have protective modifying effect on cognitive development of PKU patients.http://www.sciencedirect.com/science/article/pii/S2214426921001178PhenylketonuriaLate-diagnosedUntreatedIntellectual disabilityModifier geneSHANK |
| spellingShingle | K. Klaassen M. Djordjevic A. Skakic B. Kecman R. Drmanac S. Pavlovic M. Stojiljkovic Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier Molecular Genetics and Metabolism Reports Phenylketonuria Late-diagnosed Untreated Intellectual disability Modifier gene SHANK |
| title | Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier |
| title_full | Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier |
| title_fullStr | Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier |
| title_full_unstemmed | Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier |
| title_short | Untreated PKU patients without intellectual disability: SHANK gene family as a candidate modifier |
| title_sort | untreated pku patients without intellectual disability shank gene family as a candidate modifier |
| topic | Phenylketonuria Late-diagnosed Untreated Intellectual disability Modifier gene SHANK |
| url | http://www.sciencedirect.com/science/article/pii/S2214426921001178 |
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