SDHB and endocrine system disorder: In contrast, many disease-associated genes were categorized as missense and/or LOF tolerant, including several in which the role of heterozygous variation and endocrine disease is less established [e.g.,growth hormone receptor (GHR)] or was previously associated with reduced disease penetrance [e.g.,succinate dehydrogenase A (SDHA), succinate dehydrogenase B (SDHB)].