Table 2.

Clinical features of DM2 patients with and without R894X mutation. C/X-CCTG and R894X carriers; C/R-CCTG only carriers; F female; M male.

Feature	DM2 subjects
	C/X (n = 18 patients)				C/R (n = 35 patients)
	Nr. of patients (of 18)	Mean age at onset	F : M	Nr. of families	Nr. of patients (of 35)	Mean age at onset	F : M	Nr. of families
Clinical myotonia	15	33	12 : 3	5	12	36	7 : 5	6
EMG myotonia	17	35	14 : 3	5	24	38	16 : 8	8
Muscle weakness	8	36	5 : 3	4	15	38	12 : 3	7
Proximal muscle pain	7	35	4 : 3	4	5	39	5 : 0	6
Cataracts	7	39	6 : 1	4	14	43	2 : 1	9
Cardiac arrhythmia	1	25	1 : 0	1	2	31	10 : 5	2
Abnormal serum levels of CK, γGT or cholesterol	8	35	6 : 2	3	15	37	22 : 13	13