Letters to the Editor PULMONARY FUNCTION IN INDIVIDUALS HETEROZYGOUS FOR CYSTIC FIBROSIS
To the Editor: The twenty-eighth annual meeting of the American Society of Human Genetics (San Diego, California, October 1977) included a symposium on cystic fibrosis. A statement was made by one of the speakers that little was known about pulmonary function in individuals who are heterozygous for the cystic fibrosis gene and that studies to bear on this would be most informative. We wish to call the attention of geneticists to the very thorough study by Hallet et al. [I] on pulmonary function in 132 heterozygotes. Their evidence-based on medical history, physical examination, chest roentgenograms, pulmonary function tests, and family history -strongly suggests that heterozygotes have no respiratory abnormalities or liability for diseases of the respiratory system. FRANK E. SPEIZER PETER V. TISHLER
Channing Laboratory 180 Longwood Avenue Boston, Massachusetts 02115
REFERENCES 1. HALLETT WY, KNUDSON AG JR, MASSEY FJ JR: Absence of detrimental effect of the carrier state for the cystic fibrosis gene. Am Rev Respir Dis 92:714-724, 1965 ANALYSES OF DATA ON RATES OF CYTOGENETIC DISORDERS IN LIVE BIRTHS
To the Editor: In a discussion of our summaries of the data on rates of chromosome abnormalities in the newborn [1], Robinson asserts that pooling data from different sources could result in misleading inferences "in any attempt to understand the epidemiological picture" [2]. He cites in this regard the sex ratio of 1.96 in the total of the six populations we discussed, taking it as "evidence of probable nonrandomness" in the populations and inferring that, for this reason, the findings are suspect. This would be the case if the sex bias in these studies had not been acknowledged or taken into account. Robinson ignores or overlooks the following: (1) one large study and part of another were specifically limited to males; and (2) in our summary the rates of autosomal abnormalities were stratified by sex, and the totals were adjusted for the differential sex compositions of the populations involved. Certainly the available studies of newborns are heterogeneous, and pooling results may mask significant differences between them. This does not mean, however, that inferences derived from careful analysis of the results of such studies will not be 330
To the Editor: The twenty-eighth annual meeting of the American Society of Human Genetics (San Diego, California, October 1977) included a symposium on cystic fibrosis. A statement was made by one of the speakers that little was known about pulmonary function in individuals who are heterozygous for the cystic fibrosis gene and that studies to bear on this would be most informative. We wish to call the attention of geneticists to the very thorough study by Hallet et al. [I] on pulmonary function in 132 heterozygotes. Their evidence-based on medical history, physical examination, chest roentgenograms, pulmonary function tests, and family history -strongly suggests that heterozygotes have no respiratory abnormalities or liability for diseases of the respiratory system. FRANK E. SPEIZER PETER V. TISHLER
Channing Laboratory 180 Longwood Avenue Boston, Massachusetts 02115
REFERENCES 1. HALLETT WY, KNUDSON AG JR, MASSEY FJ JR: Absence of detrimental effect of the carrier state for the cystic fibrosis gene. Am Rev Respir Dis 92:714-724, 1965 ANALYSES OF DATA ON RATES OF CYTOGENETIC DISORDERS IN LIVE BIRTHS
To the Editor: In a discussion of our summaries of the data on rates of chromosome abnormalities in the newborn [1], Robinson asserts that pooling data from different sources could result in misleading inferences "in any attempt to understand the epidemiological picture" [2]. He cites in this regard the sex ratio of 1.96 in the total of the six populations we discussed, taking it as "evidence of probable nonrandomness" in the populations and inferring that, for this reason, the findings are suspect. This would be the case if the sex bias in these studies had not been acknowledged or taken into account. Robinson ignores or overlooks the following: (1) one large study and part of another were specifically limited to males; and (2) in our summary the rates of autosomal abnormalities were stratified by sex, and the totals were adjusted for the differential sex compositions of the populations involved. Certainly the available studies of newborns are heterogeneous, and pooling results may mask significant differences between them. This does not mean, however, that inferences derived from careful analysis of the results of such studies will not be 330
