Living with phenylketonuria in adulthood: The PKU ATTITUDE study

Dietary treatment is the cornerstone of therapy for phenylketonuria (PKU), but adherence to low- phenylalanine diet progressively decreases after adolescence. We designed a survey to characterize the dietary habits of Italian adult PKU patients and to identify psychological factors influencing disease perception and adherence to diet. Participants to the survey (n = 111; response rate 94%) were asked to complete a structured questionnaire. Patients appeared to have an altered perception and awareness of the disease. About 40% of them did not consider PKU a disease and, despite declaring regular monitoring of phenylalanine levels (85%), nearly half of them reported a high plasma value over the last 6 months (>600 μmol/L, 48%) or were unable to specify it (31%). Adherence to PKU diet was unsatisfactory, with increased consumption of natural protein sources and reduced daily use of amino-acid supplements (<4-5 times/day in 82% patients). In addition to the intrinsic characteristics of AA formula (palatability, ease of use), the most important factor influencing their consumption was the increased social pressure associated with their use (55%). Plasma phenylalanine periodical measurements (61%) and examinations at metabolic centers (49%) were considered relevant for compliance to diet. In Italian adult PKU patients dietary management was found to be inadequate, likely due to inappropriate perception and knowledge of the disease, and lack of awareness of the negative impact of poor metabolic control in adult life. Clinicians should consider implementing more intense and tailored educational measures, as well as structured transitional care processes.

Long-term continuous N-carbamylglutamate treatment in frequently decompensated propionic acidemia: a case report

Background

Propionic acidemia is a rare autosomal recessive inherited metabolic disorder that can inhibit the synthesis of N-acetylglutamate, the obligatory activator in urea synthesis, leading to hyperammonemia. N-carbamylglutamate ameliorates hyperammonemia in decompensated propionic acidemia. The effects of long-term continuous N-acetylglutamate administration in such patients are unknown. We report our clinical experience with continuous administration of N-acetylglutamate for 6 years in a patient with propionic acidemia frequently presenting with hyperammonemia.

Case presentation

A male Caucasian patient with frequently decompensated propionic acidemia and hyperammonemia was admitted 78 times for acute attacks during the first 9 years of his life. Continuous daily treatment with oral N-carbamylglutamate 100 mg/kg (50 mg/kg after 6 months) was initiated. During 6 years of treatment, he had a significant decrease in his mean plasma ammonia levels (75.7 μmol/L vs. 140.3 μmol/L before N-carbamylglutamate therapy, p < 0.005 [normal range 50–80 μmol/L]) and fewer acute episodes (two in 6 years).

Conclusion

Our results suggest a benefit of N-acetylglutamate administration outside the emergency setting. If this observation is confirmed, future studies should aim to optimize the dosage and explore effects of the dosage requirements on other drugs and on protein tolerance.

PARK2 Microduplication: Clinical and Molecular Characterization of a Further Case and Review of the Literature

We report on a patient with psychomotor deficits, language delay, dyspraxia, skeletal anomalies, and facial dysmorphisms (hirsutism, right palpebral ptosis, a bulbous nasal tip with enlarged and anteverted nares, and a mild prominent antihelix stem). Using high-resolution SNP array analysis, we identified a 0.49-Mb microduplication in chromosome 6q26 inherited from the mother involving the PARK2 gene: arr[hg19] 6q26(162,672,821-163,163,143)×3 mat. To the best of our knowledge, this is the third patient to date described in whom a 6q26 microduplication encompassing only the PARK2 gene has been reported in medical literature. The PARK2 gene is a neurodevelopmental gene that was initially discovered as one of the causes of autosomal recessive juvenile Parkinson disease and subsequently reported to be linked to autism spectrum disorders and attention-deficit hyperactivity disorders. We provide an overview of the literature on PARK2 microduplications and further delineate the associated phenotype. Taken together, our findings confirm the involvement of this gene in neurodevelopmental disorders and are useful to strengthen the hypothesis that, although with variable expressivity and incomplete penetrance, the PARK2 microduplication is associated with a new emerging neurodevelopmental delay syndrome. However, clinical and molecular evaluations of more patients with the microduplication are needed for full delineation of this syndrome.

High rate of spontaneous normalization of celiac serology in a cohort of 446 children with type 1 diabetes: a prospective study

OBJECTIVE

In children with type 1 diabetes mellitus (T1DM), elevated levels of antitissue transglutaminase (anti-tTG) antibody may spontaneously normalize, despite continued consumption of gluten. We aimed to investigate the prevalence of spontaneous normalization of anti-tTG levels and the existence of factors predictive for this outcome.

RESEARCH DESIGN AND METHODS

All children referred from 2002 to 2012 were screened for celiac disease (CD) at diabetes onset and at specific intervals. In the presence of a high anti-tTG titer or clinical symptoms, children were offered endoscopy, and asymptomatic patients with a low anti-tTG titer were invited to a second serological test after 6 months of eating a gluten-containing diet.

RESULTS

The study included 446 children. Of these, 65 (14.5%) became positive for celiac serology: 38 (58%) had a persistently elevated anti-tTG titer and 27 (41%) fluctuating anti-tTG titer; 18 (28%) became negative. The prevalence of positive CD autoimmunity and overt CD was 14.3% (95% CI 11-17) and 8.5% (95% CI 5-10), 15- and 8-times higher than the general pediatric population, respectively. Asymptomatic children older than 9.1 years at T1DM onset had the lowest risk to develop CD.

CONCLUSIONS

Serum anti-tTG levels decreased spontaneously in 40% of children with T1DM and became negative in 20%, despite gluten consumption. This finding supports the hypothesis of a state of temporary positivity of celiac serology in children with diabetes. In absence of clinical symptoms or signs of CD, histological confirmation of the disease and the gluten-free diet should be postponed to avoid unnecessary procedures and reduce an additional psychological burden.