TY  - CONF
AU  - Klaassen, Kristel
AU  - Šinžar, Ksenija
AU  - Stanković, Sara
AU  - Đorđević Milošević, Maja
AU  - Kecman, Božica
AU  - Anđelković, Marina
AU  - Skakić, Anita
AU  - Spasovski, Vesna
AU  - Ugrin, Milena
AU  - Komazec, Jovana
AU  - Parezanović, Marina
AU  - Stevanović, Nina
AU  - Pavlović, Sonja
AU  - Stojiljković, Maja
PY  - 2023
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/2142
AB  - Introduction: Phenylketonuria (PKU) is the most frequent inborn disorder of amino acid metabolism
caused by variants in human phenylalanine hydroxylase gene (PAH).
Methods: In thisstudy (an update for the time period of 10 years, with patientsfrom our previousstudies included) a total of 109 PKU patients from Serbia were analyzed. They were classified into three phenotypic categories in accordance with pre-treatment plasma phenylalanine level: classic PKU, mild PKU
and mild hyperphenylalaninemia. For genetic analyses, we combined Sanger sequencing, MLPA and
next generation sequencing to identify disease-causing variantsin PAH gene, which were further classified using ACMG classification. Additionally, we used in silico and/or eukaryotic expression studiesto assess the effect of novel genetic variants identified in our patients.
Results: Disease-causing variants were identified in 217 of 218 alleles, reaching detection rate of 99.5%.
We detected a total of 32 different variants, of which 29 previously described and three novel ones:
p.Gln226Lys, p.Pro244His and p.Pro416Leu. In silico and/or eukaryotic expression studies confirmed pathogenic effect of all novel genetic variants. The most frequent variant was p.Leu48Ser (31.2%), followed
by p.Arg408Trp (13.8%), p.Ile306Val (9.2%). p.Glu390Gly (5%), p.Pro281Leu (4.6%), and p.Arg261Gln
(3.2%). All detected disease-causing variants were classified as pathogenic using ACMG classification.
Conclusion: Our study brings the updated spectrum of molecular genetic data, variant classification
and detailed phenotypic characteristicsfor PKU patientsfrom Serbia. Therefore, ourstudy contributesto
better understanding of molecular landscape of PKU in Europe and to general knowledge on genotype–
phenotype correlation in PKU.
PB  - Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade
C3  - CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia
T1  - Molecular basis of phenylketonuria in Serbia: an update
EP  - 93
SP  - 93
UR  - https://hdl.handle.net/21.15107/rcub_imagine_2142
ER  - 

@conference{
author = "Klaassen, Kristel and Šinžar, Ksenija and Stanković, Sara and Đorđević Milošević, Maja and Kecman, Božica and Anđelković, Marina and Skakić, Anita and Spasovski, Vesna and Ugrin, Milena and Komazec, Jovana and Parezanović, Marina and Stevanović, Nina and Pavlović, Sonja and Stojiljković, Maja",
year = "2023",
abstract = "Introduction: Phenylketonuria (PKU) is the most frequent inborn disorder of amino acid metabolism
caused by variants in human phenylalanine hydroxylase gene (PAH).
Methods: In thisstudy (an update for the time period of 10 years, with patientsfrom our previousstudies included) a total of 109 PKU patients from Serbia were analyzed. They were classified into three phenotypic categories in accordance with pre-treatment plasma phenylalanine level: classic PKU, mild PKU
and mild hyperphenylalaninemia. For genetic analyses, we combined Sanger sequencing, MLPA and
next generation sequencing to identify disease-causing variantsin PAH gene, which were further classified using ACMG classification. Additionally, we used in silico and/or eukaryotic expression studiesto assess the effect of novel genetic variants identified in our patients.
Results: Disease-causing variants were identified in 217 of 218 alleles, reaching detection rate of 99.5%.
We detected a total of 32 different variants, of which 29 previously described and three novel ones:
p.Gln226Lys, p.Pro244His and p.Pro416Leu. In silico and/or eukaryotic expression studies confirmed pathogenic effect of all novel genetic variants. The most frequent variant was p.Leu48Ser (31.2%), followed
by p.Arg408Trp (13.8%), p.Ile306Val (9.2%). p.Glu390Gly (5%), p.Pro281Leu (4.6%), and p.Arg261Gln
(3.2%). All detected disease-causing variants were classified as pathogenic using ACMG classification.
Conclusion: Our study brings the updated spectrum of molecular genetic data, variant classification
and detailed phenotypic characteristicsfor PKU patientsfrom Serbia. Therefore, ourstudy contributesto
better understanding of molecular landscape of PKU in Europe and to general knowledge on genotype–
phenotype correlation in PKU.",
publisher = "Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade",
journal = "CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia",
title = "Molecular basis of phenylketonuria in Serbia: an update",
pages = "93-93",
url = "https://hdl.handle.net/21.15107/rcub_imagine_2142"
}

Klaassen, K., Šinžar, K., Stanković, S., Đorđević Milošević, M., Kecman, B., Anđelković, M., Skakić, A., Spasovski, V., Ugrin, M., Komazec, J., Parezanović, M., Stevanović, N., Pavlović, S.,& Stojiljković, M.. (2023). Molecular basis of phenylketonuria in Serbia: an update. in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia
Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade., 93-93.
https://hdl.handle.net/21.15107/rcub_imagine_2142

Klaassen K, Šinžar K, Stanković S, Đorđević Milošević M, Kecman B, Anđelković M, Skakić A, Spasovski V, Ugrin M, Komazec J, Parezanović M, Stevanović N, Pavlović S, Stojiljković M. Molecular basis of phenylketonuria in Serbia: an update. in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia. 2023;:93-93.
https://hdl.handle.net/21.15107/rcub_imagine_2142 .

Klaassen, Kristel, Šinžar, Ksenija, Stanković, Sara, Đorđević Milošević, Maja, Kecman, Božica, Anđelković, Marina, Skakić, Anita, Spasovski, Vesna, Ugrin, Milena, Komazec, Jovana, Parezanović, Marina, Stevanović, Nina, Pavlović, Sonja, Stojiljković, Maja, "Molecular basis of phenylketonuria in Serbia: an update" in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia (2023):93-93,
https://hdl.handle.net/21.15107/rcub_imagine_2142 .

TY  - CONF
AU  - Jocić, Nikola
AU  - Parezanović, Marina
AU  - Anđelković, Marina
AU  - Stevanović, Nina
AU  - Ugrin, Milena
AU  - Spasovski, Vesna
AU  - Klaassen, Kristel
AU  - Stanković, Sara
AU  - Komazec, Jovana
AU  - Pavlović, Sonja
AU  - Stojiljković, Maja
AU  - Skakić, Anita
PY  - 2023
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/2141
AB  - Introduction: Glycogen storage disease type Ib (GSD-Ib) is characterized by a deficiency of glucose-6-
phosphate translocase (G6PT) encoded by the SLC37A4 gene, affecting glucose homeostasis and disrupting autophagy. Recent findings suggest that G6PT may also play a role in autophagy and
glycogen-selective autophagy (glycophagy) activation independent of its transport function. To investigate this hypothesis, two groups of GSD-Ib patients carrying variants with different effects on G6PT
transport activity and stability (p.Asn27Lys and p.Leu348Valfs*53), were compared to the control group
of subjects.
Methods: The relative expression levels of SLC37A4 gene, autophagy (mTOR, ULK1, PRKAG1), and glycophagy markers(GABARAPL1, GAA, STBD1) were assessed in mononuclear cells of GSD Ib patients(four
carrying p.Asn27Lys and four carrying p.Leu348Valfs*53 variant) compared to control group using RTqPCR. Statistical analysis was performed using one-way ANOVA followed by a post-hoc t-test.
Results: The p.Asn27Lys group exhibited 1.5-2.5 times higher expression of SLC37A4 and autophagy
markers, while the p.Leu348Valfs*53 group showed downregulation by approximately 50% compared to
the control group. Glycophagy markers were increased twofold in both patient groups, except for GAA,
which had similar expression levels as the control group.
Conclusion: Individuals carrying the p.Asn27Lys variant display the presence of SLC37A4 transcript in
their cells, which correlates with autophagy activation. Conversely, in patients with the p.Leu348Valfs*53
variant SLC37A4 is downregulated, indicating compromised autophagy activation. These findings support the role of G6PT in autophagy activation, independent of itstransport activity. Furthermore, the elevated expression of glycophagy markers observed in both patient groups can be attributed to the
accumulated glycogen.
PB  - Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade
C3  - CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia
T1  - Investigation of the role of the glucose-6-phosphate translocase in the activation of autophagy and glycogen-selective autophagy in glycogen storage disease type IB patients
EP  - 92
SP  - 92
UR  - https://hdl.handle.net/21.15107/rcub_imagine_2141
ER  - 

@conference{
author = "Jocić, Nikola and Parezanović, Marina and Anđelković, Marina and Stevanović, Nina and Ugrin, Milena and Spasovski, Vesna and Klaassen, Kristel and Stanković, Sara and Komazec, Jovana and Pavlović, Sonja and Stojiljković, Maja and Skakić, Anita",
year = "2023",
abstract = "Introduction: Glycogen storage disease type Ib (GSD-Ib) is characterized by a deficiency of glucose-6-
phosphate translocase (G6PT) encoded by the SLC37A4 gene, affecting glucose homeostasis and disrupting autophagy. Recent findings suggest that G6PT may also play a role in autophagy and
glycogen-selective autophagy (glycophagy) activation independent of its transport function. To investigate this hypothesis, two groups of GSD-Ib patients carrying variants with different effects on G6PT
transport activity and stability (p.Asn27Lys and p.Leu348Valfs*53), were compared to the control group
of subjects.
Methods: The relative expression levels of SLC37A4 gene, autophagy (mTOR, ULK1, PRKAG1), and glycophagy markers(GABARAPL1, GAA, STBD1) were assessed in mononuclear cells of GSD Ib patients(four
carrying p.Asn27Lys and four carrying p.Leu348Valfs*53 variant) compared to control group using RTqPCR. Statistical analysis was performed using one-way ANOVA followed by a post-hoc t-test.
Results: The p.Asn27Lys group exhibited 1.5-2.5 times higher expression of SLC37A4 and autophagy
markers, while the p.Leu348Valfs*53 group showed downregulation by approximately 50% compared to
the control group. Glycophagy markers were increased twofold in both patient groups, except for GAA,
which had similar expression levels as the control group.
Conclusion: Individuals carrying the p.Asn27Lys variant display the presence of SLC37A4 transcript in
their cells, which correlates with autophagy activation. Conversely, in patients with the p.Leu348Valfs*53
variant SLC37A4 is downregulated, indicating compromised autophagy activation. These findings support the role of G6PT in autophagy activation, independent of itstransport activity. Furthermore, the elevated expression of glycophagy markers observed in both patient groups can be attributed to the
accumulated glycogen.",
publisher = "Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade",
journal = "CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia",
title = "Investigation of the role of the glucose-6-phosphate translocase in the activation of autophagy and glycogen-selective autophagy in glycogen storage disease type IB patients",
pages = "92-92",
url = "https://hdl.handle.net/21.15107/rcub_imagine_2141"
}

Jocić, N., Parezanović, M., Anđelković, M., Stevanović, N., Ugrin, M., Spasovski, V., Klaassen, K., Stanković, S., Komazec, J., Pavlović, S., Stojiljković, M.,& Skakić, A.. (2023). Investigation of the role of the glucose-6-phosphate translocase in the activation of autophagy and glycogen-selective autophagy in glycogen storage disease type IB patients. in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia
Institute of Molecular Genetics and Genetic Engineering (IMGGE), University of Belgrade., 92-92.
https://hdl.handle.net/21.15107/rcub_imagine_2141

Jocić N, Parezanović M, Anđelković M, Stevanović N, Ugrin M, Spasovski V, Klaassen K, Stanković S, Komazec J, Pavlović S, Stojiljković M, Skakić A. Investigation of the role of the glucose-6-phosphate translocase in the activation of autophagy and glycogen-selective autophagy in glycogen storage disease type IB patients. in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia. 2023;:92-92.
https://hdl.handle.net/21.15107/rcub_imagine_2141 .

Jocić, Nikola, Parezanović, Marina, Anđelković, Marina, Stevanović, Nina, Ugrin, Milena, Spasovski, Vesna, Klaassen, Kristel, Stanković, Sara, Komazec, Jovana, Pavlović, Sonja, Stojiljković, Maja, Skakić, Anita, "Investigation of the role of the glucose-6-phosphate translocase in the activation of autophagy and glycogen-selective autophagy in glycogen storage disease type IB patients" in CoMBoS2 – the Second Congress of Molecular Biologists of Serbia, Abstract Book – Trends in Molecular Biology, Special issue 06-08 October 2023, Belgrade, Serbia (2023):92-92,
https://hdl.handle.net/21.15107/rcub_imagine_2141 .