Csilla Somogyi

Metabolism of carnitine in phenylacetic acid-treated rats and in patients with phenylketonuria

The effect of metabolites accumulating in phenylketonuria (PKU) was investigated on carnitine metabolism in rats and in patients with PKU. Of phenylacetic acid (PEAA), phenylpyruvic acid and homogentisic acid the PEAA was found to be the most effective in inhibiting carnitine biosynthesis in rats. Following 60 min, a single intraperitoneal dose of PEAA the relative conversion rate, i. e. the hydroxylation, of tracer [Me-(3)H]butyrobetaine to [Me-(3)H]carnitine decreased from 62.2+/-6.00% to 39.4+/-5.11% (means+/-S.E.M., P<0.01) in the liver, in the only organ doing this conversion in rats. The conversion of loading amount of unlabeled butyrobetaine to carnitine was also markedly reduced. The impaired hydroxylation of butyrobetaine was reflected by a reduced free and total carnitine levels in the liver and a reduced total carnitine concentration in the plasma. PEAA decreased the hepatic level of glutamic acid and alpha-ketoglutaric acid (alpha-KG), suggesting a mechanism for the reduced flux through the butyrobetaine hydroxylase enzyme, because alpha-KG is an obligatory co-enzyme. In the plasma and urine of PKU patients on unrestricted diet, markedly decreased total carnitine levels were detected. In the liver of PEAA-treated rats and urine of PKU patients, a novel carnitine derivative, phenacetyl-carnitine was verified by HPLC and gas chromatography-mass spectrometry.

Deprenyl in the treatment of patients with tetrahydrobiopterin deficiencies

Most patients suffering from tetrahydrobiopterin (BH 4 ) deficiency show an inadequate clinical outcome. Besides the administration of synthetic BH 4 or phenylalanine-restricted diet, neurotransmitter substitution with L-Dopa plus carbidopa (10:1) and 5-hydroxytryptophan is required. Motor and cognitive performances fluctuate apparently at random, especially when higher doses are required. To improve the clinical outcome and to avoid the late side-effects of the traditional L-Dopa treatment, an additional selective monoamine oxidase (MAO) B inhibitor, Deprenyl (selegiline), was introduced (Schuler et al 1995). Here we report on the clinical outcome of 8 patients with BH 4 deficiency, including our 7 years of experiences with additional deprenyl therapy.

Molecular and clinical analysis of patients with classic and Duarte galactosemia in western Hungary

ZusammenfassungHINTERGRUND: Die klassische Galaktosämie ist eine autosomal rezessiv vererbte Erkrankung, die durch eine gestörte Aktivität der Galactose-1-phosphat-Uridyltransferase verursacht wird und die im Rahmen eines Neugeborenen-Screenings erkannt werden kann. In Ungarn wurde das Neugeborenen-Screening 1976 eingeführt, es wird in 2 Zentren durchgeführt. Ziel der vorliegenden Studie war die molekulare Charakteriserung des Genotyps und die Analyse der Genotyp-Phänotyp-Korrelation bei Patienten mit der klassischen bzw. mit der Variante der Galaktosämie. PATIENTEN UND METHODEN: DNS Proben von 40 Patienten wurden mittels Polymerase-Kettenreaktion, gefolgt von direkter Sequenzierung untersucht. Die klinischen Daten wurden im Hinblick auf die gefundenen Genotypen analysiert. ERGEBNISSE: 16 verschiedene Sequenzvariationen wurden identifiziert, wobei auch 2 neue Missense-Mutationen (p.S297P, p.E146D) erfasst wurden. Die zwei am häufigsten gefundenen Mutationen waren p.Q188R und p.K285N mit einer Allel-Häufigkeit von 45% bzw. 31,2%. SCHLUSSFOLGERUNGEN: Die klinisch am schwersten verlaufenden Phänotypen waren in unserer Bevölkerung mit p.Q188R, p.K285N, p.X380R, p.S297P, p.M142K, p.R.204X, p.Q169K, und p.R407P Mutationen assoziiert. Die Manifestationen hängen aber von anderen genetischen und auch Umweltfaktoren ab.SummaryBACKGROUND: Classic galactosemia is an autosomal recessively inherited disorder caused by deficient activity of the enzyme galactose-1-phosphate uridyltransferase. The disorder can be detected by newborn screening and in Hungary the national screening program was launched in 1976 with two screening centers. The aim of this study was the molecular characterization of the genotypes and analysis of genotype-phenotype correlation among patients with classic or variant galactosemia. PATIENTS AND METHODS: DNA samples from 40 patients were analyzed by polymerase chain reaction followed by direct sequencing. RESULTS: 16 different sequence variations were identified, including two novel missense mutations (p.S297P, p.E146D). The two most common mutations were p. Q188R and p.K285N with allele frequencies of 45% and 31.2%, respectively. Clinical data were evaluated with respect to the genotypes found. CONCLUSIONS: The most serious clinical phenotypes in our population were associated with mutations p. Q188R, p.K285N, p.X380R, p.S297P, p.M142K, p.R.204X, p.Q169K and p.R407P, but manifestations depend on other genetic and environmental factors.

High frequencies of biotinidase (BTD) gene mutations in the Hungarian population

Biotinidase deficiency, an autosomal recessively inherited disorder, is characterized by neurologic and cutaneous symptoms and can be detected by newborn screening. In Hungary the national screening programme was launched in 1989 with two screening centres. Over 1,070,000 neonates from western Hungary were screened for biotinidase deficiency in the Budapest Screening Centre between 1989 and December 2008. In this period, 57 patients with profound or partial biotinidase deficiency from 50 families were identified through routine newborn screening. The incidence of the disorder in western Hungary is 1 in 18,700, which is about three times the worldwide incidence. Twenty-four different mutations were identified in patients including the c.406delC novel mutation in exon 3, which is a frameshift mutation. To better understand the background of the unusually high disease incidence, 100 healthy subjects from the Hungarian population were screened by PCR and RFLP for the frequencies of p.D444H, p.Q456H and p.A171T;p.D444H, the three most common BTD mutations. The frequencies were found to be 5.5, 0.5 and 0%, respectively. The results demonstrate that the frequencies of two of the most common biotinidase variant alleles are higher in the Hungarian population than in other Caucasian populations. This and the presence of a unique Hungarian mutation may explain the high incidence of biotinidase deficiency in Hungary.

[Frequencies of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles in the Hungarian population].

UNLABELLED Classical galactosaemia is an autosomal recessively inherited disorder caused by deficient activity of the enzyme galactose-1-phosphate uridyltransferase (GALT), which can be detected by newborn screening. The p.N314D mutation defines two variant forms of the GALT enzyme, the Los Angeles and Duarte, depending on the presence of additional base changes. AIM The aim of our study was to analyze a healthy Hungarian population for the frequencies of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles. METHODS DNA samples from 100 subjects were analyzed by polymerase chain reaction, followed by digestion with restriction endonucleases. RESULTS The frequencies of the p.N314D, the Los Angeles and the Duarte variants were 11.5%, 2.5% and 9%, respectively. CONCLUSIONS The allele frequencies of the Los Angeles and Duarte variant alleles in the Hungarian population correlate well with the allele frequencies in other healthy Caucasian populations.

A Los Angeles és Duarte galaktóz-1-foszfát-uridil- transzferáz-variánsok allélgyakorisága a magyar populációban

UNLABELLED Classical galactosaemia is an autosomal recessively inherited disorder caused by deficient activity of the enzyme galactose-1-phosphate uridyltransferase (GALT), which can be detected by newborn screening. The p.N314D mutation defines two variant forms of the GALT enzyme, the Los Angeles and Duarte, depending on the presence of additional base changes. AIM The aim of our study was to analyze a healthy Hungarian population for the frequencies of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles. METHODS DNA samples from 100 subjects were analyzed by polymerase chain reaction, followed by digestion with restriction endonucleases. RESULTS The frequencies of the p.N314D, the Los Angeles and the Duarte variants were 11.5%, 2.5% and 9%, respectively. CONCLUSIONS The allele frequencies of the Los Angeles and Duarte variant alleles in the Hungarian population correlate well with the allele frequencies in other healthy Caucasian populations.

A Los Angeles és Duarte galaktóz-1-foszfát-uridil-transzferáz-variánsok allélgyakorisága a magyar populációban@@@Frequencies of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles in the Hungarian population

UNLABELLED Classical galactosaemia is an autosomal recessively inherited disorder caused by deficient activity of the enzyme galactose-1-phosphate uridyltransferase (GALT), which can be detected by newborn screening. The p.N314D mutation defines two variant forms of the GALT enzyme, the Los Angeles and Duarte, depending on the presence of additional base changes. AIM The aim of our study was to analyze a healthy Hungarian population for the frequencies of the Los Angeles and Duarte galactose-1-phosphate uridyltransferase variant alleles. METHODS DNA samples from 100 subjects were analyzed by polymerase chain reaction, followed by digestion with restriction endonucleases. RESULTS The frequencies of the p.N314D, the Los Angeles and the Duarte variants were 11.5%, 2.5% and 9%, respectively. CONCLUSIONS The allele frequencies of the Los Angeles and Duarte variant alleles in the Hungarian population correlate well with the allele frequencies in other healthy Caucasian populations.