Changing beliefs about role of genetics in body weight irrelevant to weight loss

see Genetic causal attributions for weight status and weight loss during a behavioral weight gain prevention intervention

Holding a belief that body weight is controlled by genetic factors can influence behavior and motivation to lose weight, but beliefs may not affect weight loss. In this issue, McVay et al. report that nearly half of participants in a weight-maintenance study who believed that genes control their weight changed their minds after a year of participation, compared with a control group. The researchers state that this is the first report of change in perceptions about genetic causality for weight due to a weight-gain intervention program. However, change in attitude about the role of genetics in body weight did not affect weight loss after a year of study participation. In fact, participants who attributed their weight to genetics lost more weight than those who did not attribute their weight to genetics. By contrast, in the study control group, those who attributed their weight to genetics gained more weight after 18 months than those who did not attribute their weight to genetics. The data were obtained from the Shape Program, a trial that enrolled 185 black women between 25 and 44 years old. All study participants had a body mass index in the overweight range at enrollment. The study included behavior change goals and counseling, in addition to free access to local gyms. The research team hypothesized that changing a person’s attitudes about the role of genetics may be an active ingredient in the intervention, but their results showed no association between change in attitudes and change in weight. —Karyn Hede, News Editor

Genetics of Charcot-Marie-Tooth disease gets even more complex

see The role of combined SNV and CNV burden in patients with distal symmetric polyneuropathy

The neurological disorder Charcot-Marie-Tooth (CMT) disease is already among the most complex of the well-characterized genetic disorders, but it just got even more complicated. With a prevalence of 1 in 2,500, it is among the most common of inherited neurologic disorders. Although molecular studies have found all forms of Mendelian inheritance patterns in CMT, most cases can be traced to the peripheral myelin protein 22 (PMP22) gene. Pehlivan et al. evaluated 200 confirmed CMT patients in whom the genetic cause could not be identified using standard diagnostic techniques. The research team reports the first disease-associated autosomal recessive duplication with copy-number variants (CNVs) in a rare neuropathy gene, NDRG1. Using whole-exome sequencing (WES) combined with array comparative genomic hybridization, the researchers identified underlying genetic variants in five patients, detecting new CNVs in MPZ (two cases), PRICKLE1, KIF24, and NDRG1. The study revealed that in complex cases of unknown origin, WES combined with CNV analysis is necessary to elucidate the underlying genetics. The findings suggest that both single-nucleotide variants and CNVs can occur in multiple CMT genes and that these complex underlying genetics may contribute to complicated neurological CMT cases. —Karyn Hede, News Editor