Previous PET imaging studies have demonstrated mixed findings regarding dopamine D2/D3 receptor availability in obese relative to non-obese humans. Nonspecific D2/D3 radioligands do not allow for separate estimation of D2 receptor (D2R) and D3 receptor (D3R) subtypes of the D2 receptor family, which may play different roles in behavior and are distributed differently throughout the brain. These radioligands are also displaceable by endogenous dopamine, confounding interpretation of differences in receptor availability with differing levels of dopamine release. The present study used PET imaging with the D2R-selective radioligand (N-[11C] methyl)benperidol ([11C]NMB), which is non-displaceable by endogenous dopamine, to estimate D2R specific binding (BPND) and its relationship to body mass index (BMI) and age in 15 normal-weight (mean BMI = 22.6 kg/m2) and 15 obese (mean BMI = 40.3 kg/m2) men and women. Subjects with illnesses or taking medications that interfere with dopamine signaling were excluded. Striatal D2R BPND was calculated using the Logan graphical method with cerebellum as a reference region. D2R BPND estimates were higher in putamen and caudate relative to nucleus accumbens, but did not differ between normal-weight and obese groups. BMI values did not correlate with D2R BPND. Age was negatively correlated with putamen D2R BPND in both groups. These results suggest that altered D2R specific binding is not involved in the pathogenesis of obesity per se and underscore the need for additional studies evaluating the relationship between D3R, dopamine reuptake, or endogenous dopamine release and human obesity.

Wolfram syndrome is a rare autosomal recessive genetic disease characterized by insulin dependent diabetes and vision, hearing and brain abnormalities which generally emerge in childhood. Mutations in the WFS1 gene predispose cells to endoplasmic reticulum stress-mediated apoptosis and may induce myelin degradation in neuronal cell models. However, in vivo evidence of this phenomenon in humans is lacking. White matter microstructure and regional volumes were measured using magnetic resonance imaging in children and young adults with Wolfram syndrome (n = 21) and healthy and diabetic controls (n = 50). Wolfram patients had lower fractional anisotropy and higher radial diffusivity in major white matter tracts and lower volume in the basilar (ventral) pons, cerebellar white matter and visual cortex. Correlations were found between key brain findings and overall neurological symptoms. This pattern of findings suggests that reduction in myelin is a primary neuropathological feature of Wolfram syndrome. Endoplasmic reticulum stress-related dysfunction in Wolfram syndrome may interact with the development of myelin or promote degeneration of myelin during the progression of the disease. These measures may provide objective indices of Wolfram syndrome pathophysiology that will be useful in unraveling the underlying mechanisms and in testing the impact of treatments on the brain.

OBJECTIVE:To investigate daily function among individuals with Wolfram Syndrome (WFS) and examine whether any limitations are related to disease-related symptoms.METHODS:WFS (n = 31), Type 1 diabetic (T1DM; n = 25), and healthy control (HC; n = 29) participants completed the Pediatric Quality of Life Questionnaire (PEDSQL) Self and Parent Report. PEDSQL domain scores were compared among these groups and between WFS patients with and without specific disease-related symptoms. Relationships between PEDSQL scores and symptom severity as assessed by the Wolfram Unified Rating Scale (WURS) Physical Scale were also examined.RESULTS:Across most domains, the WFS group had lower PEDSQL Self and Parent Report scores than the T1DM and HC groups. WFS participants with urinary, sleep, and temperature regulation problems had lower PEDSQL scores than those without. The WURS Physical Scale correlated with Self and Parent Report PEDSQL domains. WFS group Self and Parent Reports correlated with each other.CONCLUSIONS:The WFS group reported lower daily function compared to T1DM and HC groups. Within WFS, worse symptom severity and the specific symptoms of sleep, temperature regulation, and urinary problems were associated with poorer daily function. These findings provide rationale for an increased emphasis on identifying, treating and understanding these less well-known symptoms of WFS.

Introduction Wolfram Syndrome (WFS) is a rare genetic disease associated with a variety of progressive metabolic and neurologic impairments. Previous research has focused on WFS-related impairments and biomarkers for disease progression; however, information about how WFS impacts participation in daily activities is lacking. Methods WFS (n=45; 20 children, 25 adults) participants completed an online questionnaire about activity participation. Thirty-six non-WFS comparison participants (11 children; 25 adults) completed a portion of the questionnaire. Symptom data from a subset of WFS participants (n=20) were also examined in relation to participation data. Results WFS children and adults had lower participation than non-WFS children and adults in almost all activity domains, and social and exercise-related activities were the most problematic. In the subset of WFS adults with symptom data, poorer vision, balance, gait, hearing, and overall symptom severity related to lower participation. Conclusions WFS appears to negatively impact participation in a variety of activities, and this effect may increase as people age and/or WFS progresses. The most functionally-pertinent WFS symptoms are those associated with neurodegeneration especially vision loss and walking and balance problems. This study revealed symptoms and activity domains that are most relevant for people with WFS and, thus, can inform current practice and treatment development research.