Table 1.

Neonatal lethality of fig 4 null mice on strain C57BL/6j. Timed matings between Fig 4^+/− mice were carried out to determine the age at loss for Fig 4 null mice on the congenic C57BL/6J strain background. The probability (P-value) for the predicted Mendelian inheritance of 25% was calculated with the chi-squared test.

Age	Fig 4−/−	Total	% Fig 4−/−	P-value
E14.5	4	21	19%	0.7
E16.5	4	15	27%	1.0
E17.5	2	10	20%	0.6
E18.5	5	19	26%	1.0
P3	1	87	1%	<0.0001