A Retrospective Chart Review and Infant Feeding Survey in the Irish Phenylketonuria (PKU) Population (2016-2020).

Phenylketonuria (PKU) is an inherited disorder of protein metabolism. It is generally treated using dietary management with limited intake of phenylalanine (Phe). Partial breastfeeding (BF) is encouraged among mothers of infants with PKU, together with a Phe-free mixture of synthetic amino acids. Our aim was to describe our current BF rates and complementary feeding practices, as well as examining parental experiences of infant feeding. The objective was to better understand the challenges faced by families so that improvements can be made to clinical care. A chart review was carried out on 39 PKU patients, examining the BF rate and duration, use of second stage synthetic protein (SP), and average complementary feeding age. A parental questionnaire on complementary feeding and BF experience was designed: 26% of babies were partially breastfed at three months of age; 70% of mums would like to have breastfed for longer and cited PKU as a reason for stopping; 52% of parents reported challenges during the complementary feeding process including food refusal, protein calculation, and anxiety around maintaining good Phe levels. Suggestions to improve BF continuation and duration include active promotion of the benefits and suitability, access to lactation consultant, and peer support. The delay in introducing a second stage SP may contribute to long-term bottle use for SP. Improved patient education, written resources, and support is necessary to improve food choices and long-term acceptance of SP.

Glutaric aciduria type 1: Diagnosis, clinical features and long-term outcome in a large cohort of 34 Irish patients.

Glutaric aciduria type 1 (GA1) is a rare neurometabolic disorder that can lead to encephalopathic crises and severe dystonic movement disorders. Adherence to strict dietary restriction, in particular a diet low in lysine, carnitine supplementation and emergency treatment in pre-symptomatic patients diagnosed by high-risk screen (HRS) or newborn screen (NBS) leads to a favourable outcome. We present biochemical and clinical characteristics and long-term outcome data of 34 Irish patients with GA1 aged 1-40 years. Sixteen patients were diagnosed clinically, and 17 patients by HRS, prior to introduction of NBS for GA1 in the Republic of Ireland in 2018. One patient was diagnosed by NBS. Clinical diagnosis was at a median of 1 year (range 1 month to 8 years) and by HRS was at a median of 4 days (range 3 days to 11 years). 14/18 (77.8%) diagnosed by HRS or NBS had neither clinical manifestations nor radiological features of GA1, or had radiological features only, compared to 0/16 (0%) diagnosed clinically (p < 0.001). Patients diagnosed clinically who survived to school-age were more likely to have significant cerebral palsy and dystonia (7/11; 63.6% vs. 0/13; 0%, p < 0.001). They were less likely to be in mainstream school versus the HRS group (5/10; 50% vs. 12/13; 92.3%; p = 0.012). Clinical events occurring after 6 years of age were unusual, but included spastic diplegia, thalamic haemorrhage, Chiari malformation, pituitary hormone deficiency and epilepsy. The exact aetiology of these events is unclear.