A new face and new challenges for Online Mendelian Inheritance in Man (OMIM®).

OMIM's task of cataloging the association between human phenotypes and their causative genes (the Morbid Map of the Genome) and classifying and naming newly recognized disorders is growing rapidly. Establishing the relationship between genotype and phenotype has become increasingly complex. New technologies such as genome-wide association studies (GWAS) and array comparative genomic hybridization (aCGH) define "risk alleles" that are inherently prone to substantial interpretation and modification. In addition, whole exome and genome sequencing are expected to result in many reports of new mendelian disorders and their causative genes. In preparation for the onslaught of new information, we have launched a new Website to allow a more comprehensive and structured view of the contents of OMIM and to improve interconnectivity with complementary clinical and basic science genetics resources. This article focuses on the content of OMIM, the process and intent of disease classification and nosology, and anticipated improvements in our new Website (http://www.omim.org).