Table 2. Statistical analysis of enzyme activity in children with Phelan-McDermid Syndrome.

	Citrate Synthase	Complex I Activity	Complex IV Activity	Complex II + IIIActivity	Complex IIActivity	Any Abnormality
Control Mean (SD)	12.7 (5.1)	6.8 (2.0)	0.31 (0.10)	0.092 (0.03)	0.194 (0.08)
Normal Range	2.7–22.7	2.9–10.7	0.11–0.51	0.032–0.152	0.03–0.35
Above Normal, %, p value	8% (4/51), 0.04	14% (7/51), <0.0001	2% (1/51), 0.93	8% (3/40), 0.08	5% (2/40), 0.26	25% (13/51), <0.0001
Below Normal, %, p value	0% (0/51), 1.0	29% (15/51), <0.0001	14% (7/51), <0.0001	0% (0/40), 1.0	0% (0/40), 1.0	45% (21/51), <0.0001
Outside Normal %, p value	8% (4/51), 0.25	43% (22/51), <0.0001	16% (8/51), <0.005	8% (3/40), 0.08	5% (2/40), 0.26	59% (30/51), <0.0001
PMS Mean (SD)	10.7 (6.1)	5.8 (3.8)	0.23 (0.12)	0.09 (0.07)	0.18 (0.09)
Mean Difference, t & p value	1.72, 0.09	1.42, 0.16	5.00, <0.0001	0.09, 0.93	0.81, 0.41
Variance Difference, F & p value	1.50, 0.04	3.64, <0.00001	1.42, 0.07	4.80, <0.00001	1.13, 0.03

For Phelan-McDermid Syndrome participants, significantly more enzyme activity values were outside the normal range for complex I and IV, but not complexes II or II + III. Complex IV activity was significantly lower in Phelan-McDermid Syndrome participants as compared to controls. Variance in complex I and complex II + II were significantly different between Phelan-McDermid Syndrome participants and controls.