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  • 1980-1984  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 58 (1981), S. 396-404 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hemoglobins M and unstable hemoglobins cause clinical syndromes that are transmitted in autosomal dominant fashion. Pedigrees of 50 probands with de novo mutations producing unstable Hb disease or Hb M disease were compiled. Cases were ascertained (1) by screening the relevant literature published from 1950 through 1980 and (2) through personal communication. Additional pedigree data on several published cases were collected, and a depository containing all available information rekated to de novo Hb mutants was established. The 50 probands were born in 14 countries between 1922 and 1976. Paternity was tested in 36% of the cases, and no instance of false paternity was noted. The data were used to test for an association of advanced parental age with the appearance of de novo mutants. Paternal ages at the probands' births ranged from 20 to 50 years, with a mean of 32.7 years. Maternal ages ranged from 18 to 43 years, with a mean of 28.5 years. For each year and country (or, where necessary, for the nearest possible year and/or a demographically similar country), the cumulative frequency distributions of the ages of parents who had a child in that country and year were computed; the ages of each proband's father and mother were then expressed as percentiles on these distributions. The distribution of paternal age percentiles was shifted toward the upper end of the range, with 11 of the 50 paternal ages falling between the 90th and 100th percentiles. The distribution of maternal age percentiles was more complex, with one peak (10 of 50 ages) falling between the 30th and 40th percentiles and a second peak (10 of 50 ages), between the 90th and 100th percentiles. These distributions, though suggestive of an association of advanced parental age and the appearance of de novo mutations that cause unstable Hb disease or methemoglobinemic cyanosis, were not significantly different from those uniform distributions expected in the absence of a parental age effect.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 60 (1982), S. 181-188 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cases of unstable hemoglobin and hemoglobin M disease that have appeared as de novo mutants over a span of approximately 50 years were used in derivingminimal, direct estimates of mutation rates per nucleotide per generation in man. The estimates are based upon analysis of data related to 40 cases of unstable Hbs and 15 of Hbs M that arose in 13 countries. The estimated rate calculated using all de novo β-gene mutants is 7.4×10-9 per nucleotide per generation; that derived using de novo α-gene mutants is 10.0×10-9. Subsequent calculations of mutation rates per α- and β-chain gene and extrapolation of these rates to a hypothetical gene of 1000 nucleotides yield an estimated mutation rate of 8.6×10-6 per 1000 nucleotides per generation. Even though some instances of false paternity may have biased these estimates in an upward direction, underreporting of Hb M cases, and particularly of unstable hemoglobins, makes it likely that the cited values are minimal estimates of mutation rates at the molecular level.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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