Two large-scale mouse gene knockout phenotyping campaigns have provided 
extensive data on the functions of thousands of mammalian genes. The ongoing 
International Mouse Phenotyping Consortium (IMPC), with the goal of examining 
all ∼20,000 mouse genes, has examined 5115 genes since 2011, and phenotypic data 
from several analyses are available on the IMPC website 
(www.mousephenotype.org). Mutant mice having at least one human genetic 
disease-associated phenotype are available for 185 IMPC genes. Lexicon 
Pharmaceuticals' Genome5000™ campaign performed similar analyses between 2000 
and the end of 2008 focusing on the druggable genome, including enzymes, 
receptors, transporters, channels and secreted proteins. Mutants (4654 genes, 
with 3762 viable adult homozygous lines) with therapeutically interesting 
phenotypes were studied extensively. Importantly, phenotypes for 29 Lexicon 
mouse gene knockouts were published prior to observations of similar phenotypes 
resulting from homologous mutations in human genetic disorders. Knockout mouse 
phenotypes for an additional 30 genes mimicked previously published human 
genetic disorders. Several of these models have helped develop effective 
treatments for human diseases. For example, studying Tph1 knockout mice (lacking 
peripheral serotonin) aided the development of telotristat ethyl, an approved 
treatment for carcinoid syndrome. Sglt1 (also known as Slc5a1) and Sglt2 (also 
known as Slc5a2) knockout mice were employed to develop sotagliflozin, a dual 
SGLT1/SGLT2 inhibitor having success in clinical trials for diabetes. Clinical 
trials evaluating inhibitors of AAK1 (neuropathic pain) and SGLT1 (diabetes) are 
underway. The research community can take advantage of these unbiased analyses 
of gene function in mice, including the minimally studied 'ignorome' genes.