Inheritance of Kartagener syndrome

The surmised autosomal recessive inheritance of situs inversus of Kartagener syndrome is re-examined on the hypothesis that the homozygous state replaces lateralization of the viscera in normal ontogeny by an indifferent lateralization. The segregation ratio in the progeny of two carrier parents (if there were no ascertainment bias) would then be 1/8. The estimated segregation ratio under the assumption of complete (truncate) ascertainment is 0.124. The implications for genetic counseling are discussed.