Publications

OBJECTIVE

To utilize Mendelian randomization to estimate the causal association between low serum vitamin D concentrations, increased body mass index (BMI), and pediatric-onset multiple sclerosis (MS) using genetic risk scores (GRS).

METHODS

We constructed an instrumental variable for vitamin D (vitD GRS) by computing a GRS for 3 genetic variants associated with levels of 25(OH)D in serum using the estimated effect of each risk variant. A BMI GRS was also created that incorporates the cumulative effect of 97 variants associated with BMI. Participants included non-Hispanic white individuals recruited from over 15 sites across the United States (n = 394 cases, 10,875 controls) and Sweden (n = 175 cases, 5,376 controls; total n = 16,820).

RESULTS

Meta-analysis findings demonstrated that a vitD GRS associated with increasing levels of 25(OH)D in serum decreased the odds of pediatric-onset MS (odds ratio [OR] 0.72, 95% confidence interval [CI] 0.55, 0.94; = 0.02) after controlling for sex, genetic ancestry, , and over 100 non-human leukocyte antigen MS risk variants. A significant association between BMI GRS and pediatric disease onset was also demonstrated (OR 1.17, 95% CI 1.05, 1.30; = 0.01) after adjusting for covariates. Estimates for each GRS were unchanged when considered together in a multivariable model.

CONCLUSIONS

We provide evidence supporting independent and causal effects of decreased vitamin D levels and increased BMI on susceptibility to pediatric-onset MS.

BACKGROUND AND OBJECTIVES

Family members and friends of patients with advanced chronic illness are increasingly called on to assist with ever more complex medical care and treatment decisions arising late in the course of illness. Our goal was to learn about the experiences of family members and friends of patients with advanced kidney disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

As part of a study intended to identify opportunities to enhance advance care planning, we conducted semistructured interviews at the Veterans Affairs Puget Sound Health Care System with 17 family members and friends of patients with advanced kidney disease. Interviews were conducted between April of 2014 and May of 2016 and were audiotaped, transcribed, and analyzed inductively using grounded theory to identify emergent themes.

RESULTS

The following three themes emerged from interviews with patients' family members and friends: () their roles in care and planning were fluid over the course of the patient's illness, shaped by the patients' changing needs and their readiness to involve those close to them; () their involvement in patients' care was strongly shaped by health care system needs. Family and friends described filling gaps left by the health care system and how their involvement in care and decision-making was at times constrained and at other times expected by providers, depending on system needs; and () they described multiple sources of tension and conflict in their interactions with patients and the health care system, including instances of being pitted against the patient.

CONCLUSIONS

Interviews with family members and friends of patients with advanced kidney disease provide a window on the complex dynamics shaping their engagement in patients' care, and highlight the potential value of offering opportunities for engagement throughout the course of illness.

The myogenic regulatory factor MyoD has been implicated as a key regulator of myogenesis, and yet there is little information regarding its upstream regulators. We found that Deltex2 inhibits myogenic differentiation in vitro, and that skeletal muscle stem cells from Deltex2 knockout mice exhibit precocious myogenic differentiation and accelerated regeneration in response to injury. Intriguingly, Deltex2 inhibits myogenesis by suppressing transcription, and the Deltex2 knockout phenotype can be rescued by a loss-of-function allele for In addition, we obtained evidence that Deltex2 regulates MyoD expression by promoting the enrichment of histone 3 modified by dimethylation at lysine 9 at a key regulatory region of the locus. The enrichment is attributed to a Deltex2 interacting protein, Jmjd1c, whose activity is directly inhibited by Deltex2 and whose expression is required for MyoD expression in vivo and in vitro. Finally, we find that Deltex2 causes Jmjd1c monoubiquitination and inhibits its demethylase activity. Mutation of the monoubiquitination site in Jmjd1c abolishes the inhibitory effect of Deltex2 on Jmjd1c demethylase activity. These results reveal a mechanism by which a member of the Deltex family of proteins can inhibit cellular differentiation, and demonstrate a role of Deltex in the epigenetic regulation of myogenesis.