What role does MC4R play in sleep?

The provided context does not contain information about MC4R's role in sleep. In general scientific knowledge, the melanocortin-4 receptor (MC4R) is primarily known for regulating energy balance and appetite. Emerging evidence suggests it also influences sleep: animal models show MC4R knockout mice exhibit altered REM sleep and increased sleep fragmentation. Human GWAS have linked MC4R variants to sleep duration and quality, but effect sizes are modest and mechanisms remain unclear. The evidence is moderate (human observational/mechanistic). Without context-specific sources, this answer relies on general science. For clinical relevance, further studies are needed.