Estimates of PI*S and PI*Z Alpha-1 antitrypsin deficiency alleles prevalence in the Caribbean and North, Central and South America

BACKGROUND

AAT deficiency is not a rare disease, but one of the most common congenital disorders increasing susceptibility of individuals with this deficiency to both lung and liver disease as well as other several adverse health effects. Studies to develop accurate estimates of the magnitude of this genetic disorder in any given country is critical for the development of screening programs for detection, diagnosis, and treatment of those individuals and/or families at risk. In the present study, estimates of the prevalence of the two major deficiency alleles PI S and PI Z were estimated for 25 countries in the Caribbean and North, Central, and South America to supplement our previous studies on 69 countries worldwide.

METHOD

Using data on the prevalence of the two most common deficiency alleles PI S and PIZ in the mother countries that provided the majority of immigrants to these 25 countries, as well as genetic epidemiological studies on various genetic subgroups indigenous to the Caribbean and North, Central and South America it was possible to develop new formulas to estimate the numbers in each of five phenotypic classes, namely PI MS, PI MZ, PI SS, PI SZ and PI ZZ for each country.

RESULTS

When these 25 countries were grouped into six different geographic regions, the present study demonstrated striking differences when comparisons were made in numeric tables, maps and figures. Highly significant numbers of individuals at risk for AAT Deficiency were found in both the European, Mestizo and Mulatto populations for most of the 25 countries studied in the Caribbean and North, Central and South America.

CONCLUSIONS

Our studies demonstrated striking differences in the prevalence of both the PIS and PIZ alleles among these 25 countries in the Caribbean and North, Central and South America and significant numbers of individuals at risk for adverse health effects associated with AAT Deficiency in a given country. When these data are added to the results from our earlier studies on 69 countries, we now have data on AAT Deficiency in 94 of the 193 countries worldwide listed in the CIA FactBook.

PI S and PI Z alpha-1 antitrypsin deficiency worldwide. A review of existing genetic epidemiological data

BACKGROUND

AAT deficiency is not a rare disease, but one of the most common congenital disorders increasing susceptibility of deficiency individuals to both lung and liver disease as well as other several adverse health effects. Therefore, information on accurate estimates of the magnitude of alpha-1 antitrypsin deficiency in any given country is critical for the development of screening programs for detection, diagnosis, and treatment of those individuals and/or families at risk.

METHOD

Genetic epidemiological studies for alpha-1 antitrypsin deficiency made by others have been used to determine the percentages and estimates of the numbers in each of the five phenotypic classes (PI MS, PI MZ, PI SS, PI SZ, and PI ZZ) of the most common deficiency alleles: PI S and PI Z in each of 69 countries worldwide and also when grouped into 13 major geographic regions.

RESULTS

Our studies have demonstrated striking differences between these estimates when comparisons were made in numeric tables, maps and figures.

CONCLUSIONS

Our studies demonstrated striking differences in the prevalences of both the PIS and PIZ alleles among these 69 countries and the numbers at risk for AAT Deficiency in a given country in specific geographic regions. Data on the prevalence of the two major deficiency alleles as well as the numbers in those phenotypic classes known to be at risk for AAT Deficiency is considered critical for the identification of individuals at risk for adverse health effects associated with AAT Deficiency as well as the treatment and management of those individuals identified in a given country.

Estimated numbers and prevalence of PI*S and PI*Z deficiency alleles of alpha1-antitrypsin deficiency in Asia

The current study focuses on updating estimates of the numbers of individuals carrying the two most common deficiency alleles, protease inhibitor (PI)*S and PI*Z, for alpha1-antitrypsin deficiency (AT-D) in 20 Asian countries. A total of 170 cohorts with 31,177 individuals were selected from 20 Asian countries. The total AT-D populations in the countries selected were: 7,264 ZZ; 36,754 SZ; 6,672,479 MZ; 46,492 SS; and 16,881,108 MS. Marked differences among the Asian countries and regions were also found for the prevalence of the deficiency alleles PI*S and PI*Z. These numbers demonstrate that AT-D is not just a genetic disease that affects smaller numbers than various countries, for example, in Europe. There were marked differences between the prevalence of the PI*S and PI*Z deficiency alleles among these 20 Asian countries as well as among the countries within a given geographic region in Asia. The largest numbers of ZZ phenotypes (3,000-14,000) were in Afghanistan, Pakistan, Saudi Arabia and Thailand; with <1,700 in each of the remaining countries.

Alpha-1 antitrypsin deficiency in Italy: regional differences of the PIS and PIZ deficiency alleles

Background. Critical to the effective diagnosis and management of disease is information on its prevalence in a particular geographic area such as Italy. Alpha-1- antitrypsin deficiency (AAT Deficiency) is one of the most common serious hereditary diseases in the world, but its prevalence varies markedly from one country to another. AAT Deficiency affects at least 120.5 million carriers and deficient subjects worldwide for the two most prevalent deficiency alleles PIS and PIZ. This genetic disease is known to exist in Italy and is related to a high risk for development of jaundice in infants, liver disease in children and adults, and pulmonary emphysema in adults. Methods. Studies on the genetic epidemiology of AAT Deficiency has resulted in the development of a unique database that permits a unique analysis of the geographic distribution in 14 different regions located at random from Piemonte to Sicilia. Results. The use of Hardy-Weinberg statistical analysis to evaluate the distribution of these two deficiency alleles has demonstrated striking differences in the frequencies of these two deficiency alleles in these 14 different regions with 23/84 pair wise combinations significantly different (P=0.05) for PIS, and 5/84 combinations for PIZ. Conclusions. These findings demonstrate differences that impact the standards of care and diagnosis of AAT Deficiency in Italy since the prevalence of these deficiency alleles is not uniform throughout the country.

Genetic epidemiology of alpha-1 antitrypsin deficiency in North America and Australia/New Zealand: Australia, Canada, New Zealand and the United States of America

Alpha-1-antitrypsin deficiency (AAT deficiency) is one of the most common serious hereditary disorders in the world, as its affects all major racial subgroups worldwide, and there are an estimated 120.5 million carriers and deficient subjects worldwide. This genetic disease is related to susceptibility for development of jaundice in infants, liver disease in children and adults and pulmonary emphysema in adults. Moreover, AAT deficiency carrier phenotypes (PiMS and PiMZ) and deficiency allele phenotypes (PiSS, PiSZ and PiZZ) are suspected to predispose subjects to a variety of other adverse health effects. Because there is a limited database on the number of individuals affected by this disease worldwide, we have collected data on control cohorts in genetic epidemiological studies published on case-control studies in the peer-reviewed literature worldwide. Based on these data, we estimated the numbers of carriers and deficiency allele combinations for the two most common defective alleles, namely PiS and PiZ in 58 countries worldwide. The present paper focuses on the distribution of the PiS and PiZ deficiency alleles in Australia, Canada, New Zealand and the United States of America. A total of 31,042,232 individuals at risk for adverse health effects have been calculated in these four countries: 2,144,158 in Australia, 3,258,564 in Canada, 430,922 in New Zealand and 24,909,548 in the United States of America. The prevalences for all five phenotypic classes of AAT deficiency in each of these countries is as follows: Australia 1 out of 8.9, Canada 1 out of 9.8, New Zealand 1 out of 8.5 and the United States of America 1 out of 11.3. The geographical distribution of individual control cohorts and estimates of the numbers of carriers and deficiency allele phenotypes in each of these four countries are given in individual tables.

Genetic epidemiology of alpha-1 antitrypsin deficiency in southern Europe: France, Italy, Portugal and Spain

Alpha-1-antitrypsin deficiency (AAT deficiency) is one of the most common serious hereditary disorders in the world because it affects all major racial subgroups worldwide and there are at least 120.5 million carriers and deficient subjects worldwide. This genetic disease is related to a high risk for development of jaundice in infants, liver disease in children and adults, and pulmonary emphysema in adults. Moreover, AAT-deficiency carrier phenotypes (PiMS and PiMZ) and deficiency-allele phenotypes (PiSS, PiSZ, and PiZZ) are suspected to make subjects susceptible to a variety of other adverse health effects. As there is a limited database on the number of individuals affected by this disease worldwide, the authors of the present report collected data on control cohorts in genetic epidemiological studies published in the peer-reviewed literature worldwide. The data collected were used to estimate the numbers of carriers and deficiency-allele combinations for the two most common defective alleles, namely PiS and PiZ, in over 58 countries worldwide. The present report focuses on the distribution of the PiS and PiZ deficiency alleles in France, Italy, Portugal, and Spain. The total number of individuals at risk for adverse health effects were as follows: 9, 101, 739 in France; 4, 289, 566 in Italy; 2, 659, 241 in Portugal; and 8, 903, 773 in Spain. The geographical distribution of individual control cohorts and estimates of the numbers of carriers and deficiency-allele phenotypes in each of these four southern European countries are shown in individual tables and maps. This report will be followed by other reports on the remaining countries in Europe, as well as worldwide.