PRK1 has also been targeted for deletion in mouse and though it is not lethal (www.informatics.jax.org/marker/phenotypes/MGI:108022), the mice have a variety of phenotypes including increased body fat, which, is intriguingly similar to the obesity phenotype seen with CEP19 deletion. The gene discussed is PKN1; the disease is obesity due to melanocortin 4 receptor deficiency.