Mutations in exon 3 of the PAH gene causing mild hyperphenylalaninemia

Phenylketonuria (PKU), an autosomal recessive disorder caused by a deficiency of hepatic phenylalanine hydroxylase (PAH), is clinically very heterogeneous. On molecular level more than 350 mutations in the PAH gene are known to date, which in different genotype combinations could account for biochemical and clinical variability. Mutations located in exon 3 coding for a part of the regulatory domain of the PAH enzyme cause classical PKU, mild PKU, and mild hyperphenylalaninemia (MHP). We describe the phenotypic effects of seven mutations in exon 3 of the PAH gene (R68G, R68S, R71H, S87R, P89S, I95F, and A104D). We propose that mutations located between amino acid positions 71 through 94 cause MHP.

[Mutations causing hereditary hyperphenylalaninemia]

Mutations in the genes encoding different parts of phenylalanine hydroxylation system cause persistent hyperphenylalaninaemia. The most frequent form of hyperphenylalaninaemia is caused by mutations in the PAH gene. The most common variant result from defect of tetrahydrobiopterin synthase. Mutations in the PAH and PTS genes in the Polish population are presented. Genotype--phenotype correlations are discussed.

[Thrombus in the right ventricle in an infant--a good result of thrombolytic therapy with recombinant tissue plasminogen activator]

In a 2 month-old infant presenting with the symptoms of cardio-respiratory failure in the course of staphylococcal septicaemia a thrombus in the right ventricle was detected in an echocardiographic examination. Scintigraphy of the lungs revealed of microthrombosis. Thrombolytic therapy with recombinant tissue plasminogen activator (Actylise) was started on the dose of 0.5 mg/kg/hour in 7-hour constant infusion. After 5 days of treatment the thrombus was completely dissolved. No complication were observed. Indicators of serum clothing remained normal during the treatment.

[Acute renal insufficiency during Candida albicans candidiasis in a 2-month old infant]

In this paper has been described the case of 2-month old infant with acute renal insufficiency caused by mechanical obstacle of fungal bezoars. Bilateral pyelostomy has been performed and fungal masses have been washed out from kidney pelvis. The applied treatment including administration of Fluconazole intravenously caused disappearance of acute renal insufficiency. In this paper authors described pathogenesis, clinical symptoms, and treatment of urinary tract fungal infection.

Genetic background of clinical homogeneity of phenylketonuria in Poland

In order to elucidate the clinical homogeneity and severity of the hyperphenylalaninaemias in Poland, a total of 71 children with typical phenylketonuria (PKU) originating from western and northern Poland were screened for 13 mutations in the phenylalanine hydroxylase (PAH) gene. Eighty percent of all PKU alleles tested were found to carry an identified mutation. One mutation, namely the R408W mutation, accounted for more than 63% of mutant PAH alleles in Poland, the other 27% being accounted for by six mutations: IVS12nt1 (5%), IVSnt546 (5%), Y414C (4%), R252W (1.5%), R261Q (< 1%), and G272ter (< 1%). The predominance of the R408W mutation resulted in a high rate of homozygotes (35.2%) and compound heterozygotes for this mutation in children from western and northern Poland. The frequency and deleterious nature of this mutation probably accounts for the clinical homogeneity and severity of the hyperphenylalaninaemias in Poland. In addition, the high rate of the R408W mutation and its association with mutant haplotype 2 at the PAH locus in Poland give additional support to the Balto-Slavic origin of this mutant gene.