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Table 2 Overview prevalence of SMA by subtype

From: Prevalence, incidence and carrier frequency of 5q–linked spinal muscular atrophy – a literature review

Country Time point SMA Type I Quality and comparability Reference
   No of patients Population per 100,000 No of patients Population per 100,000  
 Norway (Southern + Eastern) 01/01/1983 24 573,762 4.18 1 573,762 0.17 Only included patients below 18 years of age Tangsrud_1988 [25]
 Sweden (Western) 31/12/2006 11 340,179 3.23 - - - Genetic diagnosis used
Only included patients below 16 years of age
Arkblad_2009 [23]
 Sweden (Western) 01/01/1995 10 359,676 2.78 1 359,676 0.28 Only included patients below 16 years of age Darin_2000 [24]
 Estonia 31/12/2003 - - - 2 1,351,069 0.15 Genetic diagnosis used Vaidla_2006 [34]
 United Kingdom (Northern Ireland) 30/06/1994 22 1,573,282 1.40 - - -   Hughes_1996 [110]
 United Kingdom (Northern England) 01/08/2007 56 2,991,517 1.87 3 2,991,517 0.10 Genetic diagnosis used in most cases Norwood_2009 [32]
 Germany (West‑Thüringen) 31/12/1987 - - - 3 1,778,200 0.17   Thieme_1993 [33]
 Italy (Bologna) 31/12/1989 10 152,529 6.56 - - - Only included patients below 20 years of age Merlini_1992 [22]
 Saudi Arabia (Northeast, Thugbah) 02/08/1989 3 22,630 13.26 1 22,630 4.42 In half of the cases parental consanguinity was observed al Rajeh_1993 [29]
 China (Hongkong) 30/06/2001 25 1,335,469 1.87 2 1,335,469 0.15 Partly used genetic diagnosis Chung_2003 [31]
 Canada (Toronto) 1962–1964 20.33 2,748,500 0.74 - - - Average of a three-year period Winsor_1971 [111]
Country Time point Type II Type III Type II + III Quality and comparability Reference
   No of patients Population per 100,000 No of patients Population per 100,000 No of patients Population per 100,000   
 Norway (Southern + Eastern) 01/01/1983 21 573,762 3.66 2 573,762 0.35 23 573,762 4.01 Only included patients below 18 years of age Tangsrud_1988 [25]
 Sweden (Western) 01/01/1995 4 359,676 1.11 5 359,676 1.39 9 359,676 2.50 Only included patients below 16 years of age Darin_2000 [24]
 United Kingdom (Northern England) 01/08/2007 17 2,991,517 0.57 36 2,991,517 1.20 53 2,991,517 1.77 Genetic diagnosis used in most casesa Norwood_2009 [32]
 United Kingdom (Northeast England) June 1971 - - - - - - 30 2,488,810 1.21 Type II/III patients defined as: onset of disease between birth and 8 years of age, survival above 18 months of age Pearn_1978 [41]
 Germany (West‑Thüringen) 31/12/1980 - - - - - - 29 1,785,239 1.62 Type II/III patients defined as: survival above 4 years of age
Exact number of patients not mentionedb
Thieme_1994 [43]
 Poland (Warsaw) 31/12/1985 - - - - - - 21 1,659,385 1.26 Exact number of patients not mentionedb Spiegler_1990 [42]
 Libya (Benghazi) 31/12/1986 - - - - - - 12 - 2.30 In half of the cases parental consanguinity was observed Radhakrishan_1988 [48]
 Saudi Arabia (Northeast, Thugbah) 02/08/1989 2 22,630 8.84 - - - - - - In half of the cases parental consanguinity was observed al Rajeh_1993 [29]
 China (Hongkong) 30/06/2001 9 1,335,469 0.67 14 1,335,469 1.05 23 1,335,469 1.72 Partly used genetic diagnosis Chung_2003 [31]
  1. Prevalence per 100,000 persons of the total population. Studies have been grouped by geographical region. Studies are based on clinical diagnosis, unless otherwise indicated. Indicated if described in article that different classification criteria than those in Table 1 were used
  2. a) 17 patients are classified as type III on clinical and neurophysiological findings in the absence of a confirmed mutation in the SMN1 gene
  3. b) Number of patients not described in article, calculated based on prevalence and population number