The First Study of Successful Pregnancies in Chinese patients with Phenylketonuria

Abstract

Since the inception of newborn screening programs in China in the 1990s, pregnancy among patients with inherited, metabolic disorders has become more common. This study explores the management and outcomes of planned, full-term pregnancies in patients with phenylketonuria (PKU). Married patients from 2012 to 2017 were enrolled to receive prenatal counseling and their partners were screened for heterozygous genes of phenylalanine hydroxylase (PAH). Daily intake of phenylalanine (Phe), blood Phe, obstetrical data, and offspring outcomes (e.g. developmental quotients [DQs]) were recorded. None of the paternal parents were heterozygous for PAH. A total of 6 neonates were successfully delivered, 5 males and 1 female. The mean ±SD (range) age of the mother at delivery was 26.3±4.7 (range:21.1-32.5) years old. The mean duration of Phe control before pregnancy was 5.5±1.3 (range:3.1-6.5) months. During pregnancy, the proportion of time during which blood Phe concentrations were within the clinically-recommended target range (120–360 μmol/L) was 63.2-83.5%. For the two babies born to patients with <70% of their pregnancy within the blood Phe target range, both birth weight and DQs were lower than the other four births. This is the first report of women in China with PKU who successfully gave birth to clinically healthy babies. Infant outcomes were related to maternal blood Phe management prior to and during pregnancy. In maternal PKU patients with poor compliance to dietary treatment, sapropterin dihydrochloride（6R-BH4）may be an option to improve the management of blood Phe levels.