Phenotypic variability This term can be applied to disease entities but not to individuals. It may be made obsolete in future versions of the HPO. Highly variable phenotype, even within families Clinical heterogeneity Variable phenotypic severity Highly variable phenotype and severity UMLS:C1839039 HP:0003815 Highly variable clinical phenotype HP:0003813 UMLS:C1850667 A variability of phenotypic features. Highly variable phenotype UMLS:C1837514 HP:0003822 Variable phenotype HP:0003821 UMLS:C1866210 HP:0003812 Clinical modifier