The effect of improved dietary control on cognitive and psychiatric functioning in adults with phenylketonuria: the ReDAPT study.

BACKGROUND: Phenylketonuria (PKU) is an autosomal recessive inherited disorder characterised by a deficiency in phenylalanine hydroxylase. Untreated, PKU is associated with a wide range of cognitive and psychiatric sequelae. Contemporary management guidelines recommend lifetime dietary control of phenylalanine (Phe) levels, however many individuals who discontinue dietary control subsequently suffer symptoms of anxiety, depression and disturbances to cognition. We undertook a prospective cohort study of patients with early-treated phenylketonuria who had ceased dietary control to test the hypothesis that resumption of dietary control of PKU is associated with improvements in measures of psychiatric morbidity and cognitive functioning. METHODS: We re-initiated dietary control for early-treated patients with PKU and monitored cognitive and psychiatric outcomes over a twelve-month period. Assessments included objective cognitive function (measured by cognitive proficiency index (CPI)), anxiety and depression scales. General linear mixed model (GLMM) analyses were performed to assess change in psychometric variables from baseline over twelve months after resumption of dietary control. RESULTS: A total of nine patients were recruited. Mean age was 33 years (SD = 8.75), five were female. Mean time off dietary control was 19.1 years (SD = 11.3), and mean baseline phenylalanine (Phe) levels were 1108 µmol/L (SD = 293). GLMM analysis demonstrated a positive relationship between CPI and time on diet (b = 0.56 [95% CI = 0.17, 0.95]). Age, time off diet, Phe levels and depression scores were not associated with cognitive function. There was a negative relationship between time on diet and anxiety (b = - 0.88 95% CI = [- 1.26, - 0.50]) and depression ratings (b = - 0.61, 95% CI = [- 0.95, - 0.26]). CONCLUSIONS: This study demonstrated improvements in cognitive function, anxiety, and depression ratings associated with resumption of dietary control of PKU. Raw Phe levels were not strongly associated with psychiatric or cognitive scores in this cohort. These findings support the importance of lifelong treatment for PKU in improving the cognitive and psychiatric sequelae of the disease.

Blood and brain protein levels of ubiquitin-conjugating enzyme E2K (UBE2K) are elevated in individuals with schizophrenia.

A number of recent studies have suggested the ubiquitin proteasome system (UPS) in schizophrenia is dysfunctional. The purpose of this study was to investigate UBE2K, a ubiquitin-conjugating (E2) enzyme within the UPS that has been associated with psychosis symptom severity, in the blood and brain of individuals with schizophrenia. Whole blood and erythrocytes from 128 (71 treatment-resistant schizophrenia, 57 healthy controls) individuals as well as frozen dorsolateral prefrontal cortex (DLPFC) and orbitofrontal cortex (OFC) post-mortem samples from 74 (37 schizophrenia, 37 controls) individuals were obtained. UBE2K gene expression was assayed in whole blood and DLPFC samples, whereas protein levels were assayed in erythrocytes and OFC samples. Elevated levels of UBE2K mRNA were observed in whole blood of individuals with schizophrenia (p = 0.03) but not in the DLPFC, while protein levels were raised in erythrocytes and the OFC (p < 0.001 and p = 0.002 respectively). Findings were not better explained by age, smoking, clozapine plasma levels or duration of illness. Although blood and brain samples were derived from independent samples, our findings suggest peripheral protein levels of UBE2K may serve as a surrogate of brain levels and further supports the notion of UPS dysfunction in schizophrenia. Future studies to determine the pathophysiological effects of elevated UBE2K protein levels in the brain of those with schizophrenia are warranted.

Prognostic significance of drainage to pelvic nodes at sentinel lymph node mapping in patients with extremity melanoma.

Patients undergoing sentinel lymph node (SLN) mapping for lower extremity melanoma may have drainage to pelvic nodes (DPN) in addition to superficial inguinal nodes. These nodes are not sampled routinely at SLN biopsy. Factors predicting DPN and its prognostic significance were assessed in a large cohort of patients undergoing an SLN biopsy. Three hundred and twenty five patients with single primary melanomas of the lower extremity or buttocks who underwent SLN mapping were identified from our prospective melanoma database (December 1995-October 2008). Associations of clinical and pathologic factors with DPN and time to melanoma recurrence (TTR) were analyzed by logistic and Cox regression, respectively. DPN was common, occurring in 23% of cases. Increased Breslow's thickness (P=0.007) and age (P=0.01) were associated with DPN by multivariate analysis. Patients with DPN were not more likely to have a positive SLN; however, SLN- patients with DPN showed a shorter TTR (P=0.02) in a multivariable model including thickness and ulceration. With age included in the model, DPN remained marginally associated with TTR in this group (P=0.08). The pelvic recurrence rates observed were similar in recurrent patients with DPN compared with those without DPN (39% in both groups). In conclusion, DPN occurs in almost one-quarter of patients with lower extremity melanoma and is marginally associated with a shorter TTR in SLN- patients.