Percent perinatal lethality in collagen X outbred and congenic mice.

Conservation of perinatal lethality for the outbred and congenic (C57Bl/6 and DBA/2J) collagen X transgenic mice (1.6–293Δ and 4.7–21Δ) and collagen X null (KO) mice excluded contribution of a strain-specific modifier to the variable disease phenotype. Percent perinatal lethality was calculated as the number of wasting mice around week-3 (n) divided by the total number of weaned offspring given by mutant producing parents.