The phenylalanine response curve in relation to growth and mental development in the first years of life

Abstract

Thirty‐three children with classical phenylketonuria were treated from 9 to 21 days of age onward. The standard for phenylalanine concentration was 0.2‐0.5 mmol/1. During the first years of life phenylalanine concentrations were measured once every two to six weeks. For each child these values were graphically plotted in so‐called phenylalanine response curve. Growth and mental development indices were assessed at about one and two years of age. Measurements for weight, height and head circumference were normal at one month of age, showed significant decline at the age of one year but were restored for normal values at the age of two. No associations were found with phenylalanine parameters. Mental development indices at one and two years were not different from normal. Significant negative correlations were found between mental development indices at one year and phenylalanine values above 0.5 mmol/1. Changes in mental development indices between the first and second years of life are significantly related to the phenylalanine levels during the second year of life.

Long-Term Growth in Phenylketonuria: A Systematic Review and Meta-Analysis

“…Study characteristics of the included studies are presented in Table 1. Ten studies were conducted in Europe [19,20,22,26,27,31,32,36,37,39], one in Australia [28], and two in the United States [8,38]. Six of the studies collected longitudinal prospective data [8,19,20,28,37,39], and seven were retrospective [22,26,27,31,32,36,38].…”

“…Ten studies were conducted in Europe [19,20,22,26,27,31,32,36,37,39], one in Australia [28], and two in the United States [8,38]. Six of the studies collected longitudinal prospective data [8,19,20,28,37,39], and seven were retrospective [22,26,27,31,32,36,38]. Seven studies were published from 1983 to 1995 [8,19,20,22,37,38,39], and the remaining six were published from 2005 to 2017 [26,27,28,31,32,36].…”

“…Six of the studies collected longitudinal prospective data [8,19,20,28,37,39], and seven were retrospective [22,26,27,31,32,36,38]. Seven studies were published from 1983 to 1995 [8,19,20,22,37,38,39], and the remaining six were published from 2005 to 2017 [26,27,28,31,32,36]. A similar distribution was observed according to when the data was collected, such that in seven out of thirteen studies data collection was carried out from the early 1960s to the end of the 1990s [8,19,20,22,36,38,39].…”

“…There was heterogeneity between studies in terms of presentation of growth data, but the most frequently used method was the z-score system [19,20,22,26,27,28,31,32,36,37]. Growth data was presented only with mean anthropometric values in three studies [8,38,39], and only two studies provided both [20,31].…”

The effect of phenylalanine restricted diet on anthropometric parameters in classical phenylketonuria patients

“…Birçok çalışmada FKÜ hastalarında, hastaların aldıkları protein miktarı ile boy ölçümü arasında pozitif ilişki olduğu gösterilmiştir (16)(17)(18) . Daha önceki çalışmalarda yaşamın ilk yıllarında özellikle doğum ile 3 yaş arasında geçici büyüme geriliği olduğu belirtilmiş ve bu durum total proteinlerin yetersiz alımı ile ilişkilendirilmiştir (19,20) . Bizim çalışmamızda da, bu çalışmalara benzer şekilde ilk 3 yıl takibinde diyet tedavisi alan olgularda diyetsiz izlenen olgulara göre boy uzamalarında istatistiksel olarak anlamlı gerilik saptadık.…”