Pretreatment cognitive and neural differences between sapropterin dihydrochloride responders and non-responders with phenylketonuria

Sapropterin dihydrochloride (BH4) reduces phenylalanine (Phe) levels and improves white matter integrity in a subset of individuals with phenylketonuria (PKU) known as “responders.” Although prior research has identified biochemical and genotypic differences between BH4 responders and non-responders, cognitive and neural differences remain largely unexplored. To this end, we compared intelligence and white matter integrity prior to treatment with BH4 in 13 subsequent BH4 responders with PKU, 16 subsequent BH4 non-responders with PKU, and 12 healthy controls. Results indicated poorer intelligence and white matter integrity in non-responders compared to responders prior to treatment. In addition, poorer white matter integrity was associated with greater variability in Phe across the lifetime in non-responders but not in responders. These results underscore the importance of considering PKU as a multi-faceted, multi-dimensional disorder and point to the need for additional research to delineate characteristics that predict response to treatment with BH4

Neural correlates of working memory and its association with metabolic parameters in early-treated adults with phenylketonuria.

BACKGROUND Phenylketonuria (PKU) is an inborn error of metabolism affecting the conversion of phenylalanine (Phe) into tyrosine. Previous research has found cognitive and functional brain alterations in individuals with PKU even if treated early. However, little is known about working memory processing and its association with task performance and metabolic parameters. The aim of the present study was to examine neural correlates of working memory and its association with metabolic parameters in early-treated adults with PKU. METHODS This cross-sectional study included 20 early-treated adults with PKU (mean age: 31.4 years ± 9.0) and 40 healthy controls with comparable age, sex, and education (mean age: 29.8 years ± 8.2). All participants underwent functional magnetic resonance imaging (fMRI) of working memory to evaluate the fronto-parietal working memory network. Fasting blood samples were collected from the individuals with PKU to acquire a concurrent plasma amino acid profile, and retrospective Phe concentrations were obtained to estimate an index of dietary control. RESULTS On a cognitive level, early-treated adults with PKU displayed significantly lower accuracy but comparable reaction time in the working memory task compared to the control group. Whole-brain analyses did not reveal differences in working memory-related neural activation between the groups. Exploratory region-of-interest (ROI) analyses indicated reduced neural activation in the left and right middle frontal gyri and the right superior frontal gyrus in the PKU group compared to the control group. However, none of the ROI analyses survived correction for multiple comparisons. Neural activation was related to concurrent Phe, tyrosine, and tryptophan concentrations but not to retrospective Phe concentrations. CONCLUSION In early-treated adults with PKU, cognitive performance and neural activation are slightly altered, a result that is partly related to metabolic parameters. This study offers a rare insight into the complex interplay between metabolic parameters, neural activation, and cognitive performance in a sample of individuals with PKU

The effects of early-treated phenylketonuria on volumetric measures of the cerebellum

Past murine studies of phenylketonuria (PKU) have documented significant effects on cerebellum at both the gross and cellular levels. The profile of neurocognitive and motor difficulties associated with early-treated PKU (ETPKU) is also consistent with potential cerebellar involvement. Previous neuroanatomical studies of cerebellum in patients with PKU, however, have yielded mixed results. The objective of the present study was to further examine potential differences in cerebellar morphometry between individuals with and without ETPKU. To this end, we analyzed high resolution T1-weighted MR images from a sample of 20 individuals with ETPKU and an age-matched comparison group of 20 healthy individuals without PKU. Measurements of whole brain volume, whole cerebellum volume, cerebellar gray matter volume, and cerebellar white matter volume were collected by means of semiautomatic volumetric analysis. Data analysis revealed no significant group differences in whole brain volume, whole cerebellar volume, or cerebellar white matter volume. A significant reduction in cerebellar gray matter volume, however, was observed for the ETPKU group compared to the non-PKU comparison group. These findings expand on previous animal work suggesting that cerebellar gray matter is impacted by PKU. It is also consistent with the hypothesis that the cognitive difficulties experienced by individuals with ETPKU may be related to disruptions in gray matter. Additional studies are needed to fully elucidate the timing and extent of the impact of ETPKU on cerebellum and the associated neurocognitive consequences

The effects of tetrahydrobiopterin (BH4) treatment on brain function in individuals with phenylketonuria

AbstractPhenylketonuria (PKU) is a rare genetic condition characterized by an absence or mutation of the PAH enzyme, which is necessary for the metabolism of the amino acid phenylalanine into tyrosine. Recently, sapropterin dihydrochloride, a synthetic form of tetrahydrobiopterin (BH4), has been introduced as a supplemental treatment to dietary phe control for PKU. Very little is known regarding BH4 treatment and its effect on brain and cognition. The present study represents the first examination of potential changes in neural activation in patients with PKU during BH4 treatment. To this end, we utilized an n-back working memory task in conjunction with functional magnetic resonance imaging (fMRI) to evaluate functional brain integrity in a sample of individuals with PKU at three timepoints: Just prior to BH4 treatment, after 4weeks of treatment, and after 6months of treatment. Neural activation patterns observed for the PKU treatment group were compared with those of a demographically-matched sample of healthy non-PKU individuals who were assessed at identical time intervals. Consistent with past research, baseline evaluation revealed impaired working memory and atypical brain activation in the PKU group as compared to the non-PKU group. Most importantly, BH4 treatment was associated with improvements in both working memory and brain activation, with neural changes evident earlier (4-week timepoint) than changes in working memory performance (6-month timepoint)

A Neural Region of Abstract Working Memory

■ Over 350 years ago, Descartes proposed that the neural basis of consciousness must be a brain region in which sen-sory inputs are combined. Using fMRI, we identified at least one such area for working memory, the limited information held in mind, described by William James as the trailing edge of consciousness. Specifically, a region in the left intraparietal sulcus was found to demonstrate load-dependent activity for either visual stimuli (colored squares) or a combination of vi-sual and auditory stimuli (spoken letters). This result was repli-cated across two experiments with different participants and methods. The results suggest that this brain region, previously well known for working memory of visually presented materials, actually holds or refers to information from more than one modality.

Development of international consensus recommendations using a modified Delphi approach

Funding Information: This work was supported by BioMarin Pharmaceutical Inc . Funding Information: The content of this manuscript was based on preparatory pre-meeting activities and presentations and discussions during two advisory board meetings that were coordinated and funded by BioMarin Pharmaceutical Inc. All authors or their institutions received funding from BioMarin to attend at least one or both meetings. Additional disclosures: BKB received consulting payments from BioMarin, Shire, Genzyme, Alexion, Horizon Therapeutics, Denali Therapeutics, JCR Pharma, Moderna, Aeglea BioTherapeutics, SIO Gene Therapies, Taysha Gene Therapy, Ultragenyx, and Inventiva Pharma, participated as clinical trial investigator for BioMarin, Shire, Denali Therapeutics, Homology Medicines, Ultragenyx, and Moderna as well as received speaker fees from BioMarin, Shire, Genzyme, and Horizon Therapeutics. AH received consulting payments from BioMarin, Chiesi, Shire, Genzyme, Amicus, and Ultragenyx, participated as clinical trial investigator for Ultragenyx as well as received speaker fees from Alexion, Amicus, BioMarin, Genzyme, Nutricia, Sobi, and Takeda. ABQ received consulting payments from BioMarin, speaker fees from BioMarin, Nutricia, Vitaflo, Sanofi, Takeda, Recordati, and travel support from Vitaflo . SEC received consulting payments and speaker fees from BioMarin as well as consulting payments from Synlogic Therapeutics. COH was clinical trial investigator for BioMarin and received consulting and speaker payments from BioMarin. SCJH received consulting payments and travel support from BioMarin and Homology Medicines. NL received consulting payments from Alnylam, Amicus, Astellas, BioMarin, BridgeBio, Chiesi, Genzyme/Sanofi, HemoShear, Horizon Therapeutics, Jaguar, Moderna, Nestle, PTC Therapeutics, Reneo, Shire, Synlogic, and Ultragenyx, participated as clinical trial investigator for Aeglea, Amicus, Astellas, BioMarin, Genzyme/Sanofi, Homology, Horizon, Moderna, Pfizer, Protalix, PTC Therapeutics, Reneo, Retrophin/Travere therapeutics, Shire, and Ultragenyx, as well as received speaker fees from Cycle Pharmaceuticals, Leadiant and Recordati. MCM II received consulting payments from BioMarin, Horizon Therapeutics, Rhythm Pharmaceuticals, Applied Therapeutics, Cycle Therapeutics, and Ultragenyx. ALSP received speaker fees from BioMarin. JCR received consulting payments from Applied Pharma Research, Merck Serono, BioMarin, Vitaflo, and Nutricia, speaker fees from Applied Pharma Research, Merck Serono, BioMarin Pharmaceutical, Vitaflo, Cambrooke, PIAM, LifeDiet, and Nutricia, as well as travel support from Applied Pharma Research, Merck Serono, BioMarin, Vitaflo, Cambrooke, PIAM, and Nutricia. SS received consulting payments, research grants, speaker fees, and travel support from BioMarin and participated as clinical trials investigator for BioMarin. ASV received consulting payments from BioMarin, Horizon Therapeutics, and Ultragenyx and participated as clinical trial investigator for Acadia, Alexion, BioMarin, Genzyme, Homology Medicines, Kaleido, Mallinckrodt, and Ultragenyx. JV received consulting payments from BioMarin, LogicBio Pharmaceuticals, Sangamo Therapeutics, Orphan Labs, Synlogic Therapeutics, Sanofi, Axcella Health, Agios Pharmaceuticals, and Applied Therapeutics as well as travel grants from BioMarin and LogicBio Pharmaceuticals. MW received consulting payments, speaker fees, and travel support from BioMarin, and participated as clinical trial investigator for Mallinckrodt, Roche, Wave, Cycle Therapeutics, and Intrabio. ACM participated in strategic advisory boards and received honoraria as a consultant and as a speaker for Merck Serono, BioMarin, Nestlé Health Science (SHS), Applied Pharma Research, Actelion, Retrophin, Censa, PTC Therapeutics, and Arla Food. Funding Information: Ideally, access to (neuro)psychological/psychiatric support should assist adolescents with identifying, understanding, and reporting of PKU-specific challenges (Table 3), offering individualized recommendations on managing these challenges. Although there is no replacement for mental health services for patients with identified needs, psychosocial support from PKU peers, e.g., through PKU camps, virtual social events, etc., can at least in the short-term help to improve metabolic control by providing individuals an opportunity to participate in supportive PKU-related educational activities potentially reducing perceived social isolation [91]. In addition to PKU camps, which may be very specific to certain regions or countries, HCPs should consider encouraging involvement in local, regional, national and international PKU patient/family advocacy and social support organizations, introducing adolescents and young adults to national/international patient registries [92,93]. Besides support from PKU peers, patients can benefit from non-PKU peer support, although some adolescents and young adults with PKU may not disclose to others and may avoid eating in with others or eating in public due to potential feelings of anxiety or feelings of being ashamed of their disease. In addition, patients with PKU of all ages, but particularly vulnerable adolescents and young adults, can benefit from having the opportunity to learn about and practice strategies that help promote feelings of empowerment and self-efficacy that can be used in both familiar and unfamiliar environments where they may experience peer pressure and feel the need to ‘fit in’. For example, a role-play approach involving behavioral rehearsal, self-monitoring, goal setting, and training in problem-solving skills with emphasis on initiation and inhibition (i.e., how to say no) could be provided by parents, PKU peers, or even members of the PKU team. These types of activities can be used to teach adolescents with PKU how to react in social situations, such as dining out, helping to avoid indulging and increased risk-taking behavior, a hallmark of the adolescent period [94].This work was supported by BioMarin Pharmaceutical Inc.The content of this manuscript was based on preparatory pre-meeting activities and presentations and discussions during two advisory board meetings that were coordinated and funded by BioMarin Pharmaceutical Inc. All authors or their institutions received funding from BioMarin to attend at least one or both meetings. Additional disclosures: BKB received consulting payments from BioMarin, Shire, Genzyme, Alexion, Horizon Therapeutics, Denali Therapeutics, JCR Pharma, Moderna, Aeglea BioTherapeutics, SIO Gene Therapies, Taysha Gene Therapy, Ultragenyx, and Inventiva Pharma, participated as clinical trial investigator for BioMarin, Shire, Denali Therapeutics, Homology Medicines, Ultragenyx, and Moderna as well as received speaker fees from BioMarin, Shire, Genzyme, and Horizon Therapeutics. AH received consulting payments from BioMarin, Chiesi, Shire, Genzyme, Amicus, and Ultragenyx, participated as clinical trial investigator for Ultragenyx as well as received speaker fees from Alexion, Amicus, BioMarin, Genzyme, Nutricia, Sobi, and Takeda. ABQ received consulting payments from BioMarin, speaker fees from BioMarin, Nutricia, Vitaflo, Sanofi, Takeda, Recordati, and travel support from Vitaflo. SEC received consulting payments and speaker fees from BioMarin as well as consulting payments from Synlogic Therapeutics. COH was clinical trial investigator for BioMarin and received consulting and speaker payments from BioMarin. SCJH received consulting payments and travel support from BioMarin and Homology Medicines. NL received consulting payments from Alnylam, Amicus, Astellas, BioMarin, BridgeBio, Chiesi, Genzyme/Sanofi, HemoShear, Horizon Therapeutics, Jaguar, Moderna, Nestle, PTC Therapeutics, Reneo, Shire, Synlogic, and Ultragenyx, participated as clinical trial investigator for Aeglea, Amicus, Astellas, BioMarin, Genzyme/Sanofi, Homology, Horizon, Moderna, Pfizer, Protalix, PTC Therapeutics, Reneo, Retrophin/Travere therapeutics, Shire, and Ultragenyx, as well as received speaker fees from Cycle Pharmaceuticals, Leadiant and Recordati. MCM II received consulting payments from BioMarin, Horizon Therapeutics, Rhythm Pharmaceuticals, Applied Therapeutics, Cycle Therapeutics, and Ultragenyx. ALSP received speaker fees from BioMarin. JCR received consulting payments from Applied Pharma Research, Merck Serono, BioMarin, Vitaflo, and Nutricia, speaker fees from Applied Pharma Research, Merck Serono, BioMarin Pharmaceutical, Vitaflo, Cambrooke, PIAM, LifeDiet, and Nutricia, as well as travel support from Applied Pharma Research, Merck Serono, BioMarin, Vitaflo, Cambrooke, PIAM, and Nutricia. SS received consulting payments, research grants, speaker fees, and travel support from BioMarin and participated as clinical trials investigator for BioMarin. ASV received consulting payments from BioMarin, Horizon Therapeutics, and Ultragenyx and participated as clinical trial investigator for Acadia, Alexion, BioMarin, Genzyme, Homology Medicines, Kaleido, Mallinckrodt, and Ultragenyx. JV received consulting payments from BioMarin, LogicBio Pharmaceuticals, Sangamo Therapeutics, Orphan Labs, Synlogic Therapeutics, Sanofi, Axcella Health, Agios Pharmaceuticals, and Applied Therapeutics as well as travel grants from BioMarin and LogicBio Pharmaceuticals. MW received consulting payments, speaker fees, and travel support from BioMarin, and participated as clinical trial investigator for Mallinckrodt, Roche, Wave, Cycle Therapeutics, and Intrabio. ACM participated in strategic advisory boards and received honoraria as a consultant and as a speaker for Merck Serono, BioMarin, Nestlé Health Science (SHS), Applied Pharma Research, Actelion, Retrophin, Censa, PTC Therapeutics, and Arla Food. Publisher Copyright: © 2022 The AuthorsBackground: Early treated patients with phenylketonuria (PKU) often become lost to follow-up from adolescence onwards due to the historical focus of PKU care on the pediatric population and lack of programs facilitating the transition to adulthood. As a result, evidence on the management of adolescents and young adults with PKU is limited. Methods: Two meetings were held with a multidisciplinary international panel of 25 experts in PKU and comorbidities frequently experienced by patients with PKU. Based on the outcomes of the first meeting, a set of statements were developed. During the second meeting, these statements were voted on for consensus generation (≥70% agreement), using a modified Delphi approach. Results: A total of 37 consensus recommendations were developed across five areas that were deemed important in the management of adolescents and young adults with PKU: (1) general physical health, (2) mental health and neurocognitive functioning, (3) blood Phe target range, (4) PKU-specific challenges, and (5) transition to adult care. The consensus recommendations reflect the personal opinions and experiences from the participating experts supported with evidence when available. Overall, clinicians managing adolescents and young adults with PKU should be aware of the wide variety of PKU-associated comorbidities, initiating screening at an early age. In addition, management of adolescents/young adults should be a joint effort between the patient, clinical center, and parents/caregivers supporting adolescents with gradually gaining independent control of their disease during the transition to adulthood. Conclusions: A multidisciplinary international group of experts used a modified Delphi approach to develop a set of consensus recommendations with the aim of providing guidance and offering tools to clinics to aid with supporting adolescents and young adults with PKU.publishersversionpublishe

The Contributions of Prefrontal Cortex and Executive Control to Deception: Evidence from Activation Likelihood Estimate Meta-analyses

Previous neuroimaging studies have implicated the prefrontal cortex (PFC) and nearby brain regions in deception. This is consistent with the hypothesis that lying involves the executive control system. To date, the nature of the contribution of different aspects of executive control to deception, however, remains unclear. In the present study, we utilized an activation likelihood estimate (ALE) method of meta-analysis to quantitatively identify brain regions that are consistently more active for deceptive responses relative to truthful responses across past studies. We then contrasted the results with additional ALE maps generated for 3 different aspects of executive control: working memory, inhibitory control, and task switching. Deception-related regions in dorsolateral PFC and posterior parietal cortex were selectively associated with working memory. Additional deception regions in ventrolateral PFC, anterior insula, and anterior cingulate cortex were associated with multiple aspects of executive control. In contrast, deception-related regions in bilateral inferior parietal lobule were not associated with any of the 3 executive control constructs. Our findings support the notion that executive control processes, particularly working memory, and their associated neural substrates play an integral role in deception. This work provides a foundation for future research on the neurocognitive basis of deception