Neurocognitive outcome and mental health in children with tyrosinemia type 1 and phenylketonuria: A comparison between two genetic disorders affecting the same metabolic pathway

Psychosocial Challenges Facing Young People With Inherited Metabolic Disorders and Their Parents: A Systematic Review

Recent advancements in new-born screening have reduced the risk of life-threatening complications associated with inherited metabolic disorders. However, the risk of negative psychosocial effects on families persists. The aim of the present study was to systematically review the literature concerning the psychosocial challenges experienced by young people with metabolic conditions and their families, to inform the development of supports that meet the needs of those linked with metabolic services. The electronic databases MEDLINE, CINAHL, PsychInfo, and Psychology and Behavioural Sciences Collection were searched for studies examining psychosocial challenges reported by families with inherited metabolic conditions, over the last two decades. Five-thousand sixty-seven articles were screened for relevance. Twenty-nine studies met the inclusion criteria. Study quality and reliability were independently assessed by two reviewers. Results highlighted the myriad of physical, social, psychological and practical challenges experienced by young people with metabolic conditions and their families. These challenges included social isolation, burden of care, and learning and emotional difficulties. Findings reiterate the importance of developing peer support groups and delivering psychoeducation to families, as well as the central role psychology and social work should play in metabolic MDTs, to improve families' experiences and outcomes.

A 12-month, longitudinal, intervention study examining a tablet protein substitute preparation in the management of tyrosinemia

Protein substitutes (PS) without tyrosine (Tyr) and phenylalanine (Phe), are an essential source of synthetic protein in the treatment of tyrosinemia (HT). In the UK, the only available protein substitutes for HT are Tyr/ Phe free amino acid liquid or powders or formulations based on glycomacropeptide (CGMP). A tablet Tyr/ Phe free amino acid supplement (AAT) has now been introduced. The aim of this two-part prospective, longitudinal intervention study was to assess the efficacy, acceptability, and tolerance of AAT in children aged >8 years with HTI. Part 1: was a 28-day acceptability/ tolerance study, part 2, was a 12-month extension study examining efficacy of AAT. Anthropometry and blood Tyr/ Phe were assessed. All subjects were taking NTBC [2-(2-nitro-4-triflourothybenzoyl) cyclohexane-1, 3-dione] with a Tyr restricted diet. Eight subjects with HTI were recruited 4 boys, and 4 girls with a median age of 14.3y (range 10.4-17.3); 3 were Caucasian and 5 of Pakistani origin. The median (range) protein equivalent from PS was 60 g/d (50-60), natural protein 20 g/d (15-30), and NTBC 30 mg/d (25-80). No subjects were taking Phe supplements. Five (63%) subjects completed part 1, with 4 taking all their PS requirements as AAT. Subjects reported AAT were tasteless and had no odour. No adverse gastrointestinal symptoms were recorded, with two reporting improvements in abdominal discomfort. At 12 months, 4 subjects had a non-significant decrease in blood Tyr/ Phe compared to the 12 months pre-treatment. Median blood Tyr (μmol/ L) pre-intervention was 500 (320-590); and at 12 months, 450 (290-530). Median blood Phe (μmol/L) pre-intervention was 40 (30-40); and at 12 months 30 (30-50). Median height z scores remained unchanged, but there was a small decrease in weight z score (pre-study weight - 0.1 (-1.4 to1.1), 12 m - 0.3 (-1.4 to 1.3) and BMI (pre- study BMI 0.2 (-2 to 1.4), and 12 m, -0.1 (-2.5 to 1.5)).

Conclusion

AAT were useful for some adolescents with HTI who struggled with the taste and volume of conventional powdered and liquid PS.

Management of patients with phenylketonuria (PKU) under enzyme replacement therapy: An Italian model (expert opinion)

Objective

Phenylketonuria (PKU) is a metabolic disorder necessitating lifelong management to prevent severe neurological impairments. This paper synthesises clinical practices from Italian specialist centres to delineate a unified approach for administering pegvaliase, a novel enzyme replacement therapy for PKU.

Methods

Virtual meetings convened in September 2022, gathering a steering committee (SC) of experts from five Italian centres specialising in PKU. The SC reviewed, and discussed clinical practices, and formulated recommendations for pegvaliase treatment.

Results

The SC outlined a comprehensive treatment roadmap for PKU management with pegvaliase, emphasising the importance of multidisciplinary care teams, patient selection, pre-treatment evaluation, and education. Recommendations include initial hospital-based pegvaliase administration, regular monitoring of phenylalanine and tyrosine levels, dietary adjustments, and management of adverse events. A consensus was reached on the need for a digital database to manage treatment plans and enhance communication between healthcare professionals and patients.

Conclusion

The expert panel's consensus highlights the complexity of PKU management and the necessity for a coordinated, patient-centred approach. The recommendations aim to standardise care across Italian centres and provide a framework for integrating pegvaliase therapy into clinical practice, potentially informing international guidelines. Further research is warranted to evaluate the long-term impact of these practices on patient outcomes and quality of life.

Emotional and behavioural functioning in children with tyrosinaemia type 1

INTRODUCTION

Tyrosinaemia type I is a rare hereditary metabolic disease caused by deficiency of the enzyme involved in the breakdown of tyrosine. Since the use of nitisinone in addition to diet in 1992, survival rates have increased significantly, but more and more socio-emotional problems have become apparent. The aim of the study was the assessment the relationship between variations in serum tyrosine and phenylalanine levels and measurements of socio-emotional functioning and determination of patients' IQs.

THE AIM OF THE STUDY

was the assessment the relationship between variations in serum tyrosine and phenylalanine levels and measurements of socio-emotional functioning and determination of patients' IQs.

MATERIAL AND METHODS

Twelve children were studied, from a single centre, born between 1994 and 2012, treated with nitisinone and a low-phenylalanine and -tyrosine diet. The psychological evaluation was conducted using the parent form of the Child Behaviour Checklist (CBCL)/4-18. Additionally, the patients' IQs were measured using the Stanford-Binet 5 (SB5) Intelligence Scale. Statistical analyses were performed using PAWS software suite version 26. We found that phenylalanine variability over time correlated with measures of emotional and behavioural functioning. This relationship holds true for externalising behaviour, associated with the experience of maladjustment and aggression. Total score intellectual and cognitive function was within the norm for all patients.

CONCLUSIONS

To maintain better quality of life for patients and their families in terms of emotional and behavioural functioning, it may be important to avoid spikes (significant fluctuations) in phenylalanine levels. Regular, detailed psychological evaluations are recommended to detect potential problems and implement interventions aimed at achieving the best possible individual development and realise the intellectual and behavioural potential, thereby improving the patient's and her family's quality of life.