MGI:1927136Mice homozygous for a null allele exhibit retinal degeneration, male sterility due to absence of sperm flagella, increased body fat but no overt obesity, hydrocephalus, wide cranial sutures and a domed cranium. On a congenic background, homozygotes show neonatal lethality, congenital heart defects, cleft lip/palate, mid-facial hypoplasia, abnormal sphenoidal bones and premaxillary bones, a solitary central upper incisor, and defects in the development of cranial base midline structures.