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Table 4 Reports of phenotypes in Friedreich ataxia patients in Norwegian patients compared to other case series

From: Friedreich ataxia in Norway – an epidemiological, molecular and clinical study

Clinical feature Harding [6] Filla et al. [37] Dürr et al. [3] Schöls et al. [34] Lamont et al. [14] 2Delatycki et al. [38] McCabe et al. [39] Salehi et al. [40] Reetz et al. [41] Present study
Country of study UK Italy France Germany UK Australia Ireland Iran Europe (EFACTS) Norway
Year of publication 1981 1990 1996 1997 1997 1999 2000 2014 2015 2015
No of patients 115 80 140 38 56 51 58 22 592 27
Genetically confirmed diagnosis No No Yes Yes Yes Yes Yes Yes Yes Yes
Age at onset (years), Mean(range),Median[interquartile range] a 10.52 (1.7-27) 11.6 (2-23) 15.5 (2-51) 14.15 (5-36) 3 to 30 10.5 (SD±6.4) (1-26) - 10.8 (2-23) 15.7 (SD±10.4), 13 [9-19] 9.6 (2-20)
Age at examination (years), Mean(range),Median[interquartile range] a - 25 (8-55) - - - - - - 33.9 (SD±10.2) 32 [23-43] 24.8 (11-69)
Disease duration (years), Mean(range),Median[interquartile range] a 22.0 (SD±12.8) (2-61) 13.4 15.5 19.7 (SD±8.8) (5-42) 13.6 (SD±9.9) - - - 18.3 (SD±10.4) 17 [10-25] 15.2 (4-59)
Male:female 1:1.2 1:0.7 1:1.1 1:1.4 - 1:0.8 - 1:0.6 1:1.2 1:0.9
SARA (Standardized Rating Scale of Ataxia), mean(range), Median[interquartile range] - - - - - - - - 23 [13-21] 21.6 (6.5-38.5), 23 [13.8-32.3]
Disability stage (1-7)b, Median - - - - - - - - 5 5
GAA repeats shortest allele, Mean(range), Median[interquartile range] a - - 630 (SD±230) 800 (66-1360) 2-5 kb 739 (SD±191) 762 (333-1053) 594 (247-981) 648 [384-800] 614.6 (340-800), 700 [556-844]
GAA repeats longest allele, Mean(range), Median[interquartile range] a - - 890 (SD±230) - 2-5 kb 973 (SD±162) 885 (534-1200) - 912 [789-1050] 759.2 (340-1040), 755 [670-840]
Frataxin level in whole blood (pg/μg) - - - - - - - - - 0.198
Homozygous GAA-repeat expansion (%) - - - - - - - 100 97 93
Family history of FRDA (%) - 23.4 - - - - - - 32 20
Consanguinity (%) - 28.1 - - - - - - - 7
Intake of Idebenone (%) - - - - - - - - 27 52
Gait ataxia (%) 100 100 100 100 100 100 100 100 - 100
Limb ataxia (%) 99 94 99 100 100 100 - 100 - 100
Dysarthria (%) 97 84 91 100 91 95 93 95 - 89
Lower limb areflexia (%) 99 100 87 84 87 98 86 100 - 93
Extensor plantar reflexes (%) 89 75 79 95 96 73.5 93 90 - 74
Reduced vibratory sense (%) 73 91 78 83 87 88 89 63 - 93
Scoliosis (%) 79 94 60 84 - 78 84 - - 85
Foot deformity (%) 55 90 55 82 - 74 79 54 - 81
Gaze-evoked nystagmus (%) 20 29 40 39 - - 40 45 - 18.5
Fixation instability (%) - - - 69 - - - - - 51.8
Saccadic pursuit eye movements (%) 12 - 30 32 - - 52 - - 67
Dysphagia (%) - 30 27 76 - - - - - 78
Diabetes (%) 10 14 32c 6 - 8 7 4.5 - 7
Cardiomyopathy (echocardiography) (%) 66d 28 63 75 - 65 67 - - 48 (n=26)
Hearing loss (%)e 8 9 13 39 - - - - - 26
Reduced vision (%)e 18   13 6 - - - 9 - 22
Psychiatric symptoms (%)f - - - - - - - - - 37
Atypical (%) - - 24 25 - 8 - - - 7
Wheelchair bound (%) 72 43 - 78 - 55 - 45 - 52
Age when wheelchair-bound (years) 25.1 (SD±15.5) 26.3 (SD±7.8) 26.3 24.0 (SD±5.7) - 19.0 (SD±6.4) - - - 20.9 (SD±7.7)
Disease duration to wheelchair-bound (years) 15.5 (SD±7.41) 13.8 (SD±5.8) 10.8 (SD±6) 11.3 (SD±4.1) - 10.1 (SD±4.4) - - - 11.1 (SD±6.4)
Prognosis indexg 0.31 0.31 - 0.25 - - - - - 0.29
  1. aUnless otherwise stated (SD=Standard deviation)
  2. bDisability stage 1-7: 1:(no disability), 1:(no functional handicap but signs at examination, 2:(mild, able to run, walking unlimited), 3:(moderate, unable to run, limited walking without aid), 4:(severe, walking with one stick), 5:(walking with two sticks), 6:(unable to walk, requiring wheelchair), 7:(confined to bed)
  3. cimpaired glucose tolerance?
  4. din Hardings study based on abnormal ECG, except for 9.6 % where ECG changes regarded insignificant
  5. eBased on information given by the patients
  6. fRequiring psychiatric treatment
  7. gPrognosis index: mean disease duration in all patients in the case series/proportion of wheelchair-bound patients in the case series