Ontological phenotype standards for neurogenetics

Neurological disorders comprise one of the largest groups of human diseases. Due to the myriad symptoms and the extreme degree of clinical variability characteristic of many neurological diseases, the differential diagnosis process is extremely challenging. Even though most neurogenetic diseases are individually rare, collectively, the subgroup of neurogenetic disorders is large, comprising more than 2,400 different disorders. Recently, increasing efforts have been undertaken to unravel the molecular basis of neurogenetic diseases and to correlate pathogenetic mechanisms with clinical signs and symptoms. In order to enable computer-based analyses, the systematic representation of the neurological phenotype is of major importance. We demonstrate how the Human Phenotype Ontology (HPO) can be incorporated into these efforts by providing a systematic semantic representation of phenotypic abnormalities encountered in human genetic diseases. The combination of the HPO together with the Orphanet disease classification represents a promising resource for automated disease classification, performing computational clustering and analysis of the neurogenetic phenome. Furthermore, standardized representations of neurologic phenotypic abnormalities employing the HPO link neurological phenotypic abnormalities to anatomical and functional entities represented in other biomedical ontologies through the semantic references provided by the HPO.