Genetic and neurological evaluation of untreated and late-treated patients with phenylketonuria

Phenylketonuria in pediatric neurology practice: a series of 146 cases

The neurologic manifestations of patients with phenylketonuria treated at different ages are illustrated in this series of 146 cases, including 9 sib pairs. In addition to well-known findings such as mental retardation, autistic features, microcephaly, and tremor, motor retardation was common and responded promptly to dietary treatment. Hypotonia and diminished reflexes were more frequent findings than hypertonia. Four sib pairs showed divergent features, such as the later-treated sibling having higher function than the early-treated one. Because siblings have a similar genotype and similar environmental and dietary conditions, this observation can be explained by differences in phenylalanine transport to the brain or additional metabolic or perinatal factors influencing the neurologic outcome.

Phenylketonuria and hyperphenylalaninemia in eastern Germany: a characteristic molecular profile and 15 novel mutations

Phenylketonuria (PKU) is an important error of amino acid metabolism which results in most patients from phenylalanine hydroxylase (PAH) deficiency. PKU displays a marked genotypic heterogeneity both within and between different populations. The aim of this study was to establish the genotypic spectrum of PKU in eastern Germany, and to compare this to the distribution of mutations in western Germany. The study population included 302 patients in 290 families who were followed at treatment centers in Berlin, Leipzig and Jena. The study showed marked genotypic variability with a total of 75 mutations, including 15 that have so far not been described (eleven missense mutations, one splicing mutation, and three small deletions). One of these novel mutations, E183Q, occurred in cis to a R408W mutation. In the non-immigrant eastern German population, the frequency of R408W accounted for 40.1% of the PKU alleles. In the immigrant Turkish population of the former West Berlin, the most prevalent mutation was IVS10-11G>A (57%). There was a marked difference of the genotypic spectrum between the population studied here and the data reported from the western part of the country.