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Higher frequency of the galactose-1-phosphate uridyl transferase gene K285N mutation in the Slovenian population
Clinical Biochemistry 40 (2007) 414 – 415
Higher frequency of the galactose-1-phosphate uridyl transferase gene K285N mutation in the Slovenian population Jana Lukac-Bajalo a,⁎, Natasa Karas Kuzelicki a , Irena Prodan Zitnik a , Simona Mencej a , Tadej Battelino b a
University of Ljubljana, Faculty of Pharmacy, Chair of Clinical Biochemistry, Askerceva cesta 7, SI-1000 Ljubljana, Slovenia b University Medical Centre Ljubljana, University Children’s Hospital Ljubljana, Ljubljana, Slovenia Received 4 July 2006; received in revised form 1 November 2006; accepted 9 November 2006 Available online 5 December 2006
Abstract Objectives: To analyze a healthy Slovenian population for the frequency of the classical galactosemia allele K285N. Design and methods: DNA was analyzed by means of polymerase chain reaction and restriction fragment length polymorphism. Results: The allele frequency of the K285N mutation in Slovenian population is 0.29%. Conclusions: The allele frequency of the K285N mutation in Slovenian population is higher than in other Caucasian populations. K285N is one of the most frequent classical galactosemia mutations in the Slovenian population. © 2007 Published by The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Keywords: Galactosaemia; GALT gene; Mutation K285N; Slovenian population
Introduction Galactose-1-phosphate uridyl transferase (GALT) (EC 2.7.7.12) catalyzes the second step of the Leloir pathway of galactose metabolism, the formation of uridine diphosphate (UDP)galactose and glucose-1-phosphate from galactose-1-phosphate and UDP-glucose. Absence or severe deficiency of the enzyme activity results in classical galactosemia (McKusick 230400). The second most frequent classical galactosemia mutation among Caucasians is point mutation K285N. In some European populations it accounts for as much as 26–34% of galactosemia alleles [1–3]. The mutation is rare in individuals with nonEuropean ancestry [4,5]. Individuals homoallelic for this mutation have a severe phenotype with complete loss of enzyme activity named classical galactosemia [6]. The syndrome is characterized by failure to thrive, vomiting, diarrhea, jaundice, hepatomegaly and cataracts and can, if not treated, lead to sepsis and death. Heterozygotes for K285N mutation have approximately 50% of normal GALT activity and are asymptomatic at ⁎ Corresponding author. Fax: +386 1 42 58 031. E-mail address: [email protected] (J. Lukac-Bajalo).
birth, although there are some indications that risk for developing certain diseases, such as cataracts, later in life is increased [7]. The aim of our study was to analyze a healthy Slovenian population for the frequency of classical galactosemia allele K285N. The results, together with the results of the previous study for the frequencies of alleles Q188R, Duarte-2 and Duarte-1 [8], provide a basis for examining groups of patients with diseases associated with each mutation. Methods Three hundred and forty-six healthy volunteers (both sexes, age range 19 to 64 years) from the total Slovenian population of 2 million were screened for the frequency of the K285N mutation. The study was approved by the Ethics Committee of the Ministry of Health of Slovenia, No. 54/11/99 and informed consent was obtained from all the participants. DNA was isolated from venous blood by a salting out procedure, and polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) for the detection of the K285N mutation were performed as described previously [7,8].
0009-9120/$ - see front matter © 2007 Published by The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2006.11.004
J. Lukac-Bajalo et al. / Clinical Biochemistry 40 (2007) 414–415 Table 1 Allele frequencies of K285N mutation in different healthy populations and comparison of the results of Slovenian population with published data on other healthy populations Country, population
n
Allele Allele pa frequency of frequency of K285N (%) Q188R (%)
Slovenia 346 0.29 USA: average of all 4796 0.042 USA: Caucasian population 3244 0.062 USA: Caucasian population 2661 0.075 with European ancestry
0.14 0.23 0.29 0.32
pb
1.000 0.057 0.001 0.107 0.003 0.145 0.007
Comparison of allele frequencies of K285N and Q188R in different healthy populations. a Comparison of allele frequencies of K285N mutation between the Slovenian and other healthy populations. b Comparison of allele frequencies of K285N and Q188R in different healthy populations.
Comparisons of frequencies of K285N mutation were analyzed using the Fisher exact test. Significance was defined as p < 0.05. Results In the group of 346 healthy subjects, 2 heterozygotes (0.58%) and no homozygotes were found, giving an allele frequency of 0.29%, which is higher than in some other populations [9], although the difference is not statistically significant (Table 1). Discussion The allele frequency of mutation K285N in healthy Slovenian population is higher than in some other populations, although the difference is not statistically significant. In healthy populations the allele frequency of Q188R mutation is usually statistically significantly higher than the frequency of K285N mutation [9]. However, in healthy Slovenian population there is no significant difference between the frequencies of Q188R and K285N (Table 1). Studies of the Czech, Slovak, Polish and Austrian galactosemia populations have shown that in these populations the frequencies of K285N mutation are higher than in other European populations [1–3]. It has been suggested that this mutation could have a Slavic origin [2] and our results confirm this hypothesis. In a study of Slovenian patients with idiopathic presenile cataract, K285N mutation was associated with the formation of cataract, whereas no such association was found in
415
Q188R mutation [7]. K285N was also the only classical galactosemia mutation found in the group of Slovenian patients with premature ovarian failure [10]. This study shows that K285N mutation is one of the most frequent classical galactosemia mutations in healthy Slovenian population and it is therefore imperative that it is included in diagnostics of galactosemia and galactosemia associated diseases. Acknowledgments This study was supported in part by the Ministry of Education, Science and Sport of the Republic of Slovenia, research project no. L3-2003-0312. We thank Prof. Roger Pain for advice on the English language and Neda Grzinic for technical assistance. References [1] Greber-Platzer S, Guldberg P, Scheibenreiter S, et al. Molecular heterogeneity of classical and Duarte galactosemia: mutation analysis by gradient gel electrophoresis. Hum Mutat 1997;10:49–57. [2] Kozak L, Francova H, Fajkusova L, et al. Mutation analysis of the GALT gene in Czech and Slovak galactosemia populations: identification of six novel mutations, including a stop codon mutation (X380R). Hum Mutat 2000;15:206. [3] Zekanowski C, Radomyska B, Bal J. Molecular characterization of Polish patients with classical galactosaemia. J Inherited Metab Dis 1999;22: 679–682. [4] Manga N, Jenkins T, Jackson H, Whittaker DA, Lane AB. The molecular basis of transferase galactosaemia in South African negroids. J Inherited Metab Dis 1999;22:37–42. [5] Hirokawa H, Okano Y, Asada M, Fujimoto A, Suyama I, Isshiki G. Molecular basis for phenotypic heterogeneity in galactosaemia: prediction of clinical phenotype from genotype in Japanese patients. Eur J Hum Genet 1999;7:757–64. [6] Shin YS, Zschocke J, Das AM, Podskarbi T. Molecular and biochemical basis for variants and deficiency forms of galactose-1-phosphate uridyltransferase. J Inherited Metab Dis 1999;22:327–9. [7] Karas N, Gobec L, Pfeifer V, Mlinar B, Battelino T, Lukac-Bajalo J. Mutations in galactose-1-phosphate uridyltransferase gene in patients with idiopathic presenile cataract. J Inherited Metab Dis 2003;26(7): 699–704. [8] Lukac-Bajalo J, Marc J, Mlinar B, Karas N, Krzisnik C, Battelino T. Frequencies of Q188R and N314D mutations and IVS5-24g>A intron variation in the galactose-1-phosphate uridyl transferase (GALT) gene in the Slovenian population. Clin Chem Lab Med 2002;40:1109–13. [9] Suzuki M, West C, Beutler E. Large-scale molecular screening for galactosemia alleles in pan-ethnic population. Hum Genet 2001;109:210–5. [10] Mlinar B, Gersak K, Karas Kuzelicki N, Prodan Zitnik I, Battelino T, Lukac Bajalo J. Galactose-1-phosphate uridyl transferase gene mutations in women with premature ovarian failure. Fertil Steril 2005;84(1):253–5.
Higher frequency of the galactose-1-phosphate uridyl transferase gene K285N mutation in the Slovenian population Jana Lukac-Bajalo a,⁎, Natasa Karas Kuzelicki a , Irena Prodan Zitnik a , Simona Mencej a , Tadej Battelino b a
University of Ljubljana, Faculty of Pharmacy, Chair of Clinical Biochemistry, Askerceva cesta 7, SI-1000 Ljubljana, Slovenia b University Medical Centre Ljubljana, University Children’s Hospital Ljubljana, Ljubljana, Slovenia Received 4 July 2006; received in revised form 1 November 2006; accepted 9 November 2006 Available online 5 December 2006
Abstract Objectives: To analyze a healthy Slovenian population for the frequency of the classical galactosemia allele K285N. Design and methods: DNA was analyzed by means of polymerase chain reaction and restriction fragment length polymorphism. Results: The allele frequency of the K285N mutation in Slovenian population is 0.29%. Conclusions: The allele frequency of the K285N mutation in Slovenian population is higher than in other Caucasian populations. K285N is one of the most frequent classical galactosemia mutations in the Slovenian population. © 2007 Published by The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. Keywords: Galactosaemia; GALT gene; Mutation K285N; Slovenian population
Introduction Galactose-1-phosphate uridyl transferase (GALT) (EC 2.7.7.12) catalyzes the second step of the Leloir pathway of galactose metabolism, the formation of uridine diphosphate (UDP)galactose and glucose-1-phosphate from galactose-1-phosphate and UDP-glucose. Absence or severe deficiency of the enzyme activity results in classical galactosemia (McKusick 230400). The second most frequent classical galactosemia mutation among Caucasians is point mutation K285N. In some European populations it accounts for as much as 26–34% of galactosemia alleles [1–3]. The mutation is rare in individuals with nonEuropean ancestry [4,5]. Individuals homoallelic for this mutation have a severe phenotype with complete loss of enzyme activity named classical galactosemia [6]. The syndrome is characterized by failure to thrive, vomiting, diarrhea, jaundice, hepatomegaly and cataracts and can, if not treated, lead to sepsis and death. Heterozygotes for K285N mutation have approximately 50% of normal GALT activity and are asymptomatic at ⁎ Corresponding author. Fax: +386 1 42 58 031. E-mail address: [email protected] (J. Lukac-Bajalo).
birth, although there are some indications that risk for developing certain diseases, such as cataracts, later in life is increased [7]. The aim of our study was to analyze a healthy Slovenian population for the frequency of classical galactosemia allele K285N. The results, together with the results of the previous study for the frequencies of alleles Q188R, Duarte-2 and Duarte-1 [8], provide a basis for examining groups of patients with diseases associated with each mutation. Methods Three hundred and forty-six healthy volunteers (both sexes, age range 19 to 64 years) from the total Slovenian population of 2 million were screened for the frequency of the K285N mutation. The study was approved by the Ethics Committee of the Ministry of Health of Slovenia, No. 54/11/99 and informed consent was obtained from all the participants. DNA was isolated from venous blood by a salting out procedure, and polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) for the detection of the K285N mutation were performed as described previously [7,8].
0009-9120/$ - see front matter © 2007 Published by The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.clinbiochem.2006.11.004
J. Lukac-Bajalo et al. / Clinical Biochemistry 40 (2007) 414–415 Table 1 Allele frequencies of K285N mutation in different healthy populations and comparison of the results of Slovenian population with published data on other healthy populations Country, population
n
Allele Allele pa frequency of frequency of K285N (%) Q188R (%)
Slovenia 346 0.29 USA: average of all 4796 0.042 USA: Caucasian population 3244 0.062 USA: Caucasian population 2661 0.075 with European ancestry
0.14 0.23 0.29 0.32
pb
1.000 0.057 0.001 0.107 0.003 0.145 0.007
Comparison of allele frequencies of K285N and Q188R in different healthy populations. a Comparison of allele frequencies of K285N mutation between the Slovenian and other healthy populations. b Comparison of allele frequencies of K285N and Q188R in different healthy populations.
Comparisons of frequencies of K285N mutation were analyzed using the Fisher exact test. Significance was defined as p < 0.05. Results In the group of 346 healthy subjects, 2 heterozygotes (0.58%) and no homozygotes were found, giving an allele frequency of 0.29%, which is higher than in some other populations [9], although the difference is not statistically significant (Table 1). Discussion The allele frequency of mutation K285N in healthy Slovenian population is higher than in some other populations, although the difference is not statistically significant. In healthy populations the allele frequency of Q188R mutation is usually statistically significantly higher than the frequency of K285N mutation [9]. However, in healthy Slovenian population there is no significant difference between the frequencies of Q188R and K285N (Table 1). Studies of the Czech, Slovak, Polish and Austrian galactosemia populations have shown that in these populations the frequencies of K285N mutation are higher than in other European populations [1–3]. It has been suggested that this mutation could have a Slavic origin [2] and our results confirm this hypothesis. In a study of Slovenian patients with idiopathic presenile cataract, K285N mutation was associated with the formation of cataract, whereas no such association was found in
415
Q188R mutation [7]. K285N was also the only classical galactosemia mutation found in the group of Slovenian patients with premature ovarian failure [10]. This study shows that K285N mutation is one of the most frequent classical galactosemia mutations in healthy Slovenian population and it is therefore imperative that it is included in diagnostics of galactosemia and galactosemia associated diseases. Acknowledgments This study was supported in part by the Ministry of Education, Science and Sport of the Republic of Slovenia, research project no. L3-2003-0312. We thank Prof. Roger Pain for advice on the English language and Neda Grzinic for technical assistance. References [1] Greber-Platzer S, Guldberg P, Scheibenreiter S, et al. Molecular heterogeneity of classical and Duarte galactosemia: mutation analysis by gradient gel electrophoresis. Hum Mutat 1997;10:49–57. [2] Kozak L, Francova H, Fajkusova L, et al. Mutation analysis of the GALT gene in Czech and Slovak galactosemia populations: identification of six novel mutations, including a stop codon mutation (X380R). Hum Mutat 2000;15:206. [3] Zekanowski C, Radomyska B, Bal J. Molecular characterization of Polish patients with classical galactosaemia. J Inherited Metab Dis 1999;22: 679–682. [4] Manga N, Jenkins T, Jackson H, Whittaker DA, Lane AB. The molecular basis of transferase galactosaemia in South African negroids. J Inherited Metab Dis 1999;22:37–42. [5] Hirokawa H, Okano Y, Asada M, Fujimoto A, Suyama I, Isshiki G. Molecular basis for phenotypic heterogeneity in galactosaemia: prediction of clinical phenotype from genotype in Japanese patients. Eur J Hum Genet 1999;7:757–64. [6] Shin YS, Zschocke J, Das AM, Podskarbi T. Molecular and biochemical basis for variants and deficiency forms of galactose-1-phosphate uridyltransferase. J Inherited Metab Dis 1999;22:327–9. [7] Karas N, Gobec L, Pfeifer V, Mlinar B, Battelino T, Lukac-Bajalo J. Mutations in galactose-1-phosphate uridyltransferase gene in patients with idiopathic presenile cataract. J Inherited Metab Dis 2003;26(7): 699–704. [8] Lukac-Bajalo J, Marc J, Mlinar B, Karas N, Krzisnik C, Battelino T. Frequencies of Q188R and N314D mutations and IVS5-24g>A intron variation in the galactose-1-phosphate uridyl transferase (GALT) gene in the Slovenian population. Clin Chem Lab Med 2002;40:1109–13. [9] Suzuki M, West C, Beutler E. Large-scale molecular screening for galactosemia alleles in pan-ethnic population. Hum Genet 2001;109:210–5. [10] Mlinar B, Gersak K, Karas Kuzelicki N, Prodan Zitnik I, Battelino T, Lukac Bajalo J. Galactose-1-phosphate uridyl transferase gene mutations in women with premature ovarian failure. Fertil Steril 2005;84(1):253–5.