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Biomedical subjects

G A Danieli

Publications and source records attributed to G A Danieli.

At least 91 records · Page 5Linked to original sources
PubMed1991

Segregation and sporadic cases in families with Hunter's syndrome.

Segregation analysis on five samples of families with Hunter's syndrome (158 cases overall) shows that the mutant allele segregates in agreement with Mendelian expectations for an X linked recessive disease, but the proportion of sporadic cases is significantly lower than expected under mutation-selection equilibrium. Heterogeneity among the samples is apparent, but it is caused entirely by a sample of Ashkenazi families, whose segregation pattern has previously been interpreted as supporting the hypothesis of prenatal selection in favour of the pathological allele. Conversely, our joint analysis of the five samples by a maximum likelihood approach does not suggest segregation distortion. Possible reasons for the apparent lack of sporadic cases include the effect of ascertainment bias.

Alleles↗
PubMed1990

Segregation analysis of 1885 DMD families: significant departure from the expected proportion of sporadic cases.

The proportion of sporadic cases of Duchenne muscular dystrophy has been estimated by classical segregation analysis in a pooled sample of 1885 sibships from 7 different countries. A significant departure from the theoretical expectations based on mutation-selection equilibrium is observed (segregation frequency = 0.439 +/- 0.017; frequency of sporadic cases = 0.229 +/- 0.026, at the maximum likelihood). The occurrence of germinal mosaicism in some of the mothers of Duchenne cases may account for this peculiar finding, although a possible role of inequality of mutation rates in the two sexes cannot be ruled out.

Chromosomes, Human↗
PubMed1989

Problems in genetic counseling in a family with an "atypical" centronuclear myopathy.

Genetic counseling often deals with a rare disease the inheritance of which is not clearly established or in which genetic heterogeneity is reported. In addition, relevant parameters such as penetrance, gene frequency, and mutation rate may not be available. In this situation, establishing the risk may be very difficult. An example is presented in which Bayesian risk calculation proved to be of great help in providing precise risk estimates in a family in which an "atypical" centronuclear myopathy was segregating.

Adult↗
PubMed1987

Genetic epidemiology of myotonic dystrophy.

Prevalence rate of myotonic dystrophy (DM) was estimated in a large sample of the Italian population. Segregation analysis of the affected families suggests that subjects showing minor clinical signs, even in the absence of myotonic features, should be considered as bearers of the DM trait. An apparent excess of normal sibs among the offspring of DM subjects may be due to the late onset of the disease and possibly to a partial loss of affected individuals from the sample before diagnosis. Prevalence rate of DM in this study is estimated between 69 to 90 per million inhabitants; accordingly, DM might be the most frequent inherited neuromuscular disorder in human populations.

Adult↗
PubMed1987

Population data on benign and severe forms of X-linked muscular dystrophy.

Epidemiological data on Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD) from a large sample of the Italian population are reported. For BMD the incidence rate was found to be 5.5 X 10(-5) live-born males (lbm) and the prevalence rate, 13.1 X 10(-6); the mutation rate was estimated to be about 6.0 X 10(-6). For DMD the incidence and prevalence rates were found to be respectively 26 X 10(-5) lbm and 31.6 X 10(-6). The DMD mutation rate obtained by the Haldane formula was 86.6 X 10(-6) and by the semi-direct method, 65.6 X 10(-6). The results are discussed in the light of possible allelism of BMD and DMD.

Adult↗
PubMed1987

Sporadic cases in Duchenne muscular dystrophy. A reappraisal through segregation analysis on 988 sibships.

A new estimation of the proportion of sporadic cases in Duchenne muscular dystrophy was attempted by means of segregation analysis in a sample of 988 sibships collected on a world-wide scale by different authors. Maximum likelihood estimates of ascertainment probability (pi), segregation frequency (p), and frequency of sporadic cases (x) were calculated by Morton's equations under different hypotheses. The best fit was found for p = 0.454 +/- 0.024 and x = 0.235 +/- 0.034. The possibility that the proportion of sporadic cases might be lower than the expected 1/3 is suggested.

Gene Frequency↗
PubMed1984

Duchenne muscular dystrophy. Frequency of sporadic cases.

A segregation analysis on 135 Duchenne families from Venetia (Italy) suggests that the proportion of sporadic cases might be less than expected. Support for this view is also given by an analysis of a pooled sample including 284 additional sibships from comparable studies published previously. Several hypotheses were tested: the maximum likelihood was obtained for a segregation frequency p = 0.46 and for a proportion of sporadic cases x = 0.227 +/- 0.048.

Gene Frequency↗
PubMed1983

Esterase-6 allozymes: biochemical studies of two common and one rare variant in Drosophila melanogaster.

The biochemical properties of three allozymes coded by the Est-6 locus, two common forms (EST-6S and EST-6F) and one rare form (EST-6VF), were studied. The results show the existence of differences in isoelectric point, activity, activation energy, Km, and temperature coefficient among the three variants, especially between the two common forms and the one rare form. The specific activity of the rare enzymatic variant seems to be less affected by temperature variation. The possible significance of these findings in relation to the mechanism of reproduction is briefly discussed.

Alleles↗
PubMed1980

Duchenne muscular dystrophy: data from family studies.

In an extensive epidemiological survey of Duchenne muscular dystrophy carried out in Venetia (Italy) the incidence was found to be 28.2 X 10(-5) and female gamete mutation rate was estimated by the direct method between 61 and 35 X 10(-6). The percentage of isolated cases was 0.54. Indirect and direct estimates of this proportion suggest, however, that only a minor fraction arises from maternal mutation (from 0.11 to 0.18 of the total number of cases). Studies on pedigrees collected in the course of the survey indicate that there is a higher frequency of Duchenne carrier females than normal females in affected sibships. Additional evidence supporting the hypothesis of a reproductive heterozygote advantage and gametic selection is reported.

Female↗
PubMed1977

Duchenne muscular dystrophy. A population study.

By a general survey in the hopitals of northeast Italy, Duchenne cases have been located and identified over a 20-year period. In a more restricted area screening for Duchenne carriers has been carried out in affected families. This procedure made possible an exact estimate of the incidence rate, prevalence rate, and mutation rate in a large sample of population. Prevalence rate was found to be 34x10(-6), incidence rate about 28x10(-5), while mutation rate was found lower than 50x10(-6) by the direct method. The discrepancy between the results obtained by the Haldane formula and those obtained by the direct method for the estimate of the mutation rate is discussed.

Female↗