Table 2.

Comparison of STR-PCR with Standard PCR and PCR-Southern Blot in the Analysis of SCA7 Patients

Range of expansion	Genotypes (CAG)	N	Standard PCR	PCR- Southern	STR- PCR
Normal	9/9	5	+	n.d.	+
	9/10	1	+	n.d.	+
	10/10	16	+	n.d.	+
	10/11	3	+	n.d.	+
	10/12	4	+	n.d.	+
	10/13	2	+	n.d.	+
	10/14	1	+	n.d.	+
	10/15	1	+	n.d.	+
	10/16	1	+	n.d.	+
	11/12	1	+	n.d.	+
	11/14	1	+	n.d.	+
	12/12	1	+	n.d.	+
	13/13	1	+	n.d.	+
	12/34	1	+	n.d.	+*
Common
mutations	10/36	1	+	n.d.	+*
	11/39	1	+	n.d.	+*
	10/41	1	+	n.d.	+
	7/42	1	+	n.d.	+
	10/42	5	+	n.d.	+
	12/42	1	+	n.d.	+
	10/43	2	+	n.d.	+
	12/43	1	+	n.d.	+
	10/44	1	+	n.d.	+
	10/47	2	+	n.d.	+
	10/48	1	+	n.d.	+
	10/49	1	+	n.d.	+
	10/54	2	+	+	+
Rare large
mutations	10/58	1	+	+	+
	12/61	1	+	+	+
	10/65	1	+	+	+
	13/66	1	+	+	+
	10/77	1	+	+	+
	10/90	1	±	+	+
	13/106	1	±	+	+
	10/306	1	−	+	+

^*The fluorescent STR-primed PCR could not correctly classify the profile in the normal or expanded range. 

PCR results on the three right columns refer to the larger allele. + and − indicate the ability of a technique to identify an expansion. When ± is present, the expansion was not always detected. 

N, number of tested subjects. n.d., not done.