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Cross-sectional neuroimaging studies in non-depressed individuals have demonstrated an inverse relationship between daylight minutes and cerebral serotonin transporter; this relationship is modified by serotonin-transporter-linked polymorphic region short allele carrier status. We here present data from the first longitudinal investigation of seasonal serotonin transporter fluctuations in both patients with seasonal affective disorder and in healthy individuals. Eighty (11)C-DASB positron emission tomography scans were conducted to quantify cerebral serotonin transporter binding; 23 healthy controls with low seasonality scores and 17 patients diagnosed with seasonal affective disorder were scanned in both summer and winter to investigate differences in cerebral serotonin transporter binding across groups and across seasons. The two groups had similar cerebral serotonin transporter binding in the summer but in their symptomatic phase during winter, patients with seasonal affective disorder had higher serotonin transporter than the healthy control subjects (P = 0.01). Compared to the healthy controls, patients with seasonal affective disorder changed their serotonin transporter significantly less between summer and winter (P < 0.001). Further, the change in serotonin transporter was sex- (P = 0.02) and genotype- (P = 0.04) dependent. In the patients with seasonal affective disorder, the seasonal change in serotonin transporter binding was positively associated with change in depressive symptom severity, as indexed by Hamilton Rating Scale for Depression - Seasonal Affective Disorder version scores (P = 0.01). Our findings suggest that the development of depressive symptoms in winter is associated with a failure to downregulate serotonin transporter levels appropriately during exposure to the environmental stress of winter, especially in individuals with high predisposition to affective disorders.media-1vid110.1093/brain/aww043_video_abstractaww043_video_abstract.

AimsFabry disease, an X-linked storage disorder caused by defective lysosomal enzyme alpha-galactosidase A activity, may resemble sarcomere-gene-associated hypertrophic cardiomyopathy (HCM). The 'cardiac variant' of Fabry disease which only affects the heart may be missed unless specifically tested for. Methods and resultsWe evaluated 90 consecutively recruited HCM probands and their relatives. Probands without sarcomere-gene mutations were tested for alpha-galactosidase A gene (GLA) mutations. Of the 90 families, 31 (34%) had sarcomere gene mutations and were therefore excluded. In the remaining 59 probands, 3 (5%) had GLA mutations as follows. The first proband, a female with asymmetric septal hypertrophy (ASH), a significant left ventricular outflow tract gradient, and chronic obstructive pulmonary disease, was heterozygous for a novel missense mutation (p.N139S). The second proband, a male with ASH and multiple episodes of ventricular tachycardia, was hemizygous for a missense mutation (p.A156T). His daughter was heterozygous, but had normal enzyme activity. The third proband was a female with ASH, and no other indices of Fabry disease. She was heterozygous for a GLA missense mutation (p.G271S). She had one affected daughter but her two other children were unaffected. The affected daughter had three children, of whom two were also affected-a boy aged 8 and a daughter aged 10 years. ConclusionThis is the first report of systematic mutation screening of GLA in HCM patients without sarcomere gene mutations. GLA mutations were found in 3/90 (3%) of HCM families and in 2/20 (10%) of females without sarcomere-gene mutations. None of the probands presented other indices of Fabry disease. This, in combination with putative reversibility of cardiac changes by enzyme replacement therapy, supports systematic testing for Fabry disease. Enzyme measurements are sufficient in men, but genetic testing is needed in women.--

Metabolic dysfunction and mitochondrial involvement are recognised as part of the pathology in Huntington's Disease (HD). Post-mortem examinations of the striatum from end-stage HD patients have shown a decrease in the in vitro activity of complexes II, III and IV of the electron transport system (ETS). In different models of HD, evidence of enzyme defects have been reported in complex II and complex IV using enzyme assays. However, such assays are highly variable and results have been inconsistent. We investigated the integrated ETS function ex vivo using a sensitive high-resolution respirometric (HRR) method. The O2 flux in a whole-cell sample combined with the addition of mitochondrial substrates, uncouplers and inhibitors enabled us to accurately quantitate the function of individual mitochondrial complexes in intact mitochondria, while retaining mitochondrial regulation and compensatory mechanisms. We used HRR to examine the mitochondrial function in striata from 12-week old R6/2 mice expressing exon 1 of human HTT with 130 CAG repeats. A significant reduction in complex II and complex IV flux control ratios was found in the R6/2 mouse striatum at 12 weeks of age compared to controls, confirming previous findings obtained with spectrophotometric enzyme assays.

Fabry disease is an X-linked inherited lysosomal disorder with dysfunction of the lysosomal enzyme alpha-galactosidase A causing accumulation of glycolipids in multiple organs including the nervous system. Pain and somatosensory disturbances are prominent manifestations of this disease. Until recently disease manifestations in female carriers of Fabry disease have been questioned. To explore the frequency of symptoms and the functional and structural involvement of the nervous system in female patients we examined the presence of pain, manifestations of peripheral neuropathy and nerve density in skin biopsies in 19 female patients with Fabry disease and 19 sex- and age-matched controls. Diaries, quantitative sensory testing, neurophysiologic tests and skin biopsies were performed. Daily pain was present in 63% of patients, with a median VAS score of 4.0. Tactile detection threshold and pressure pain threshold were lower and cold detection thresholds increased in patients. Sensory nerve action potential amplitude and maximal sensory conduction velocity were not different, whereas there was a highly significant reduction in intraepidermal nerve fiber density. We found no correlation between pain VAS score, quantitative sensory testing and intraepidermal nerve fiber density. Our study demonstrates that careful evaluation of symptoms in female Fabry patients is important as small fiber disease manifestations are present, which in some cases is only detected by skin biopsy.