INCIDENCE OF CYSTIC FIBROSIS

Europe (apparently, it’s similar for Australia)• 1 in 2000-3000 new borns are affected
• There are local and regional variations
o E.g. In France, there is a high incidence in Brittany, and a lower incidence in the South
• Mutations are detected in more than 95% of the CFTR genes taken from CF patients
o Most common mutation – F508del.
o 10-15% of mutations – 5 to 10 other mutations, G542X, N1303K, G551D
o Mediterranean countries – G542X and N1303K most common
o Ethnic specific mutations as well –the incidence is related to a specific country/region

Africa
• No accurate prevalence figures for northern African countries bordering the Medieterranean
o Studies that have been done show largely European mutations (F508del., G542X and N1303K), but at different frequencies
o Some unique mutations present
• There is evidence that CF is quite common (analysis of individuals of sub-Saharan origin) and underdiagnosed
• Carrier frequency – 1 in 42  thus, the calculated expected incidence = 1 in 7056

North America
• Incidence: 1 in 3500
• CFTR mutations reflect the geographic origin of the population
o Strong relationship to Europe
• F508del mutation is the most common CF mutation in African Americans  due to ethnic mixture with Caucasians
• African CFTR mutation (3120+1G A) is the second most prevalent allele in African America CF patients
• Canada
o If the region contain people of French of British origin, their rate of incidence reflects the ancestral British and French rate.
o East to west – decrease in the frequency of F508del. – due to increase in ethnic diversity

Latin America
• Incidence ranges from 1 in 3900 to 1 in 8500
• F508del mutation is the most common cause of CF
o Higher frequency in countries with a higher proportion of individuals of Caucasian origin (e.g. Uruguay, Argentina), and vice versa (e.g.Chile)
Middle East
• Incidence ranges from 1 in 2560 to 1 in 15876
o Incidence varies according to ethnic background and the degree of consanguinity
o 65% - Arab origin
• Mutations shared with other regions of the world – F508del., N1303K, W1282X and 3120+1G>A .
o 3120+1G>A - frequent in those of African descent
o F508del – common in Lebanon and Israel
• Rare mutations throughout the Near and Middle East  rarely observed anywhere else
o A mutation may be specific for an ethnic/religious group
• Due to geographic location, indigenous founder mutations and ethnic mixture  ‘melting pot’ of genetic influences

Asia
• Japan – 1 in 100,000 to 1 in 350,000
• India – 1 in 40,000 to 1 in 100,000
o No single mutation has an incidence greater than 15%
o High heterogenous population
• Pakistan – 60% of patients with CF are homozygous for F508del
o Lower in Indian (20%) and Japanese (10%) patients

Source - From WHO

-Rushmi