Table 1.

Summary of demographic variables and significance values for the cystinosis and control groups

	Preacademic group			School-age group
	n = 50			n = 51
	Cystinosis	Control	p	Cystinosis	Control	p
	n = 26	n = 24		n = 26	n = 25
Mean Age at Testing	4 y 2 m ± 9 m	4 y 4 m ± 11 m	NS	10 y 8 m ± 3y 7 m	9 y 9 m ± 3y 3 m	NS
Mean SESa	2.27 ± 0.96	2.21 ± 1.02	NS	1.92 ± 0.84	1.84 ± 0.90	NS
Sex	13 M; 13 F	14 M; 10 F	NS	18 M; 8 F	15 M ; 10 F	NS
VIQ	97.85 ± 11.52	101.04 ± 8.76	NS	92.23 ± 13.39	102.96 ± 7.99	0.001
PIQ	90.27 ± 13.04	100.33 ± 15.32	0.02	88.27 ± 16.40	107.32 ± 15.33	<0.001

^aBased on the Hollingshead Four Factor Index of Social Status [23], with 1 being the highest and 5 being the lowest socioeconomic status

y years, m months, M male, F female, SES socioeconomic status, VIQ Verbal IQ, PIQ Performance IQ