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Biomedical subjects

G Filippi

Publications and source records attributed to G Filippi.

At least 55 records · Page 3Linked to original sources
PubMed1984

Studies on hemophilia A in Sardinia bearing on the problems of multiple allelism, carrier detection, and differential mutation rate in the two sexes.

A large survey of hemophilia A carried out with almost complete ascertainment on the island of Sardinia suggests that the variation of plasma levels of Factor VIII coagulant activity in normal individuals is largely controlled by a series of normal isoalleles or by closely linked modifiers. This variation is expected to affect the laboratory detection of the hemophilia A (HA) heterozygotes in addition to the X-inactivation-dependent mosaicism and the type of deficient mutant present in a given pedigree. The Sardinian pedigrees yielded 13 new cases of nonrecombinants between the loci for HA and glucose-6-phosphate dehydrogenase (G6PD), as well as four nonrecombinants between HA and Deutan color blindness. These findings bring to a total of 58 the number of scorable sibs and nonrecombinants thus far known for the linkage HA-G6PD. From such a figure it has been possible to infer that the 90% upper limit of meiotic recombination between the two loci is below 4%, thus justifying the application of the "linkage diagnostic test" for the detection of HA heterozygotes and the prenatal diagnosis of the hemophilic fetuses in families that segregate at both loci. In three out of the five HA pedigrees of our series that segregate also for G6PD or Deutan color blindness, the observed segregation of the combined phenotypes can be best explained by assuming the occurrence of a fresh mutation in the maternal grandfathers. Such a finding points out the opportunity to reevaluate Haldane's hypothesis of a possible higher incidence of X-linked mutations in the human male. It is anticipated that each of the issues addressed by the present study will be amenable to experimental verification as soon as suitable molecular probes become available to screen for common multiallelic DNA polymorphisms in the subtelomeric region of the X-chromosome long arm.

Alleles↗
PubMed1983

Brief report: linkage between G6PD and fragile-X syndrome.

Eighteen Sardinian pedigrees segregating for the X-fragile site syndrome were studied with respect to the segregation of the fragile site (FS) at Xq28, mental retardation, and macro-orchidism. No exception was found in the association of this symptomatic triad (MOM-X) in 41 out of 42 patients examined. The exceptional individual had micro- rather than macro-orchidism and was found to have a 47, XXY sex chromosome complement. In six informative sibships, the MOM-X syndrome was found to segregate in close linkage association with G6PD-deficiency or protan colorblindness. The maximum likelihood estimate of recombination if 6% with 90% fiducial limits between 2.5 and 19.5% and an odds ratio in favor of measurable linkage of 428:1. However, no hint of measurable linkage was found in six pedigrees segregating for G6PD and the Renpenning syndrome or other unspecified types of X-linked mental retardation. These data give strong support to the generally held hypothesis that the FS at Zq28, characteristic of the MOM-X syndrome, is a direct expression of a genetic change in the same chromosomal region. They also clearly suggest that X-linked MR without FS may be the result of different allelic mutations at the same locus.

Color Vision Defects↗
PubMed1982

Cytogenetic findings in 4952 prenatal diagnoses. An Italian collaborative study.

The development of prenatal diagnosis in Italy was made difficult by the restrictions of the old abortion law and only in recent years has a consistent number of cases been investigated. We report the experience on prenatal chromosome diagnosis of ten Italian centers participating in a collaborative study on 4952 diagnoses performed from 1972 to 1980. The main indication groups were: advanced maternal age (2882 cases), previous child with chromosome anomaly from parents with normal karyotype (847 cases), and chromosome anomaly in one parent (97 cases). The other indications for amniocentesis, including cases without a cytogenetic risk, have been assembled into a "miscellaneous" group (1126 cases). We found 125 abnormal fetal karyotypes (2.5%) of which 89 were unbalanced (1.8%). The frequencies and types of chromosome anomalies are reported in detail for each indication group and are compared with the corresponding one from the European Munich Conference. The great majority of these Italian data were not included in the Munich report.

Chromosome Aberrations↗
PubMed1981

Genetic variation in the quantitative levels of an NADP (H)-binding protein (FX) in human erythrocytes.

FX is a red cell NADP(H)-binding protein that has been well defined biochemically and immunologically but whose function is still unknown. Preliminary data indicated that the levels of this protein are significantly increased in hemizygotes, heterozygotes, and homozygotes for the G6PD Mediterranean mutant, thus raising the question of whether or not the individual variation in FX levels is more or less directly influenced by X-linked genes. The present study, based on a large series of population and family data collected in Sardinia, confirms unequivocally the above mentioned interaction, but shows at the same time that the variances in FX levels "between sibships" are 2-3 times larger than those "within sibships," when the analysis is done separately for the G6PD-normal or the G6PD-deficient sibs. From the comparison of the interclass and intraclass correlation coefficients, it appears that about 60% of the total variation of FX is of genetic origin. Moreover, the FX levels of children, analyzed in a pairwise manner, were found to be more positively correlated with those of their fathers (r = 0.39) than with those of their maternal grandfathers (0.20). This latter finding obviously favors the conclusion that "autosomal" rather than "X-linked" genes are involved in the determination of the FX levels.

Adult↗
PubMed1980

XX male with breast cancer.

We present the case of a 66-year-old XX male who developed breast cancer on the left side at the age of 61. His clinical, endocrinological and cytogenetic features are described. The presence of hypospadias and cancer in the left breast are noteworthy; the latter is very rarely found in Klinefelter syndrome patients. An outline of the pathogenesis of breast cancer in XX male patients is also given. This is the first report of an XX male with breast cancer.

Adenocarcinoma↗
PubMed1979

X pentasomy: a case and review.

A 49,XXXXX girl is reported. The most typical features of the patient are: severe mental retardation, serious dental anomalies, various anomalies of the bones, and a high rate of gonadotropins. The few similar cases so far described are reviewed to aid in delineation of this rare syndrome. The implications of Lyon's hypothesis on X-aneuploidies are also discussed.

Aneuploidy↗
PubMed1979

Simultaneous radioimmunoassay of serum testosterone and 5 alpha-dihydrotestosterone without chromatography.

When characterization of the specificity of an antiserum for radioimmunoassay (RIA) is performed by the conventional method, the conditions under which interference occurs are not respected because of the lack of specific antigen. We have studied the behavior of antisera reproducing the real environment existing in unknown samples, in which antigen, interferent and tracer complete simultaneously. A testosterone (T) antiserum and a 5 alpha-dihydrotestosterone (D) anti serum were characterized by setting up two distinct hapten recovery tests in the presence of both the hapten and the crossreactant added to steroid-free serum in various concentrations in order to reproduce multiple concentration ratios. These samples, together with the standard curves samples (prepared by 'spiking' steroid-free serum with known concentrations of T or D) were extracted and subjected to T-RIA and D-RIA without purification. The results have shown that the interferent-induced incremental ratio is a linear function of the ratio of the levels of cross-reactant and hapten via a proportionality factor inversely correlated to the antiserum specificity. By means of this function, the overestimated T and D levels found in samples after 'extraction only' have been corrected and the resulting values have shown acceptable correlation with the corresponding levels determined after column chromatography.

Cross Reactions↗
PubMed1979

Extra small metacentric chromosome identified as i(18p).

A case of a supernumerary metacentric small chromosome, diagnosed at birth, is described. The cytogenetic findings support its identification as i(18p). The clinical development from birth to 12 months is reported, with particular attention given to the psychomotor retardation and to the immunological aspect.

Chromosome Aberrations↗
PubMed1979

X-mapping in man: evidence against measurable linkage between anhidrotic ectodermal dysplasia and G6PD deficiency.

A Sardinian kindred segregating for X-linked anhidrotic ectodermal dysplasia (AED), glucose-6-phosphate dehydrogenase (G6PD) deficiency of Mediterranean type, and Xga blood antigen provides evidence against a measurable linkage between the loci for AED and G6PD. Moreover, from the segregation of the combined phenotypes in four scorable sons from two triple heterozygotes with phase known, it seems highly probable that the AED locus is nearer to the centromere than is the G6PD locus.

Blood Group Antigens↗
PubMed1979

Additional pedigree supporting the frequent origin of XXYY from consecutive meiotic non-disjunction in paternal gametogenesis.

A 48,XXYY Sardinian patient, born to a 46,XX mother heterozygous for the Gd Mediterranean mutant, and to a 46,XY father hemizygous for the same mutant, was found to have a mosaic distribution of G6PD(+) and G6PD(-) peripheral red blood cells. The most likely interpretation of this finding is that the propositus is an additional example of an XXYY zygote derived from a consecutive meiotic non-disjunction during paternal gametogenesis.

Adult↗
PubMed1979

Trisomy 20p from maternal t(3;20) translocation.

A case of trisomy 20p resulting from a maternal translocation t(3;20) is described. QM and BUdR banding techniques were used for its identification. A round face with oblique palpebral fissures, strabismus, cardiac and vertebral abnormalities, mild psychomotor retardation, together with poor coordination and speech impediment, are the most typical features of the proband.

Child, Preschool↗
PubMed1978

Triplo-X constitution of mother explains apparent occurrence of two recombinants in sibship segregating at two closely X-linked loci (G6PD and deutan).

Two male sibs believed to be examples of meiotic recombinants between the closely linked loci for G6PD deficiency of Mediterranean type and severe deutan color blindness proved to be simple segregants of a triplo-X mother of genotype d--GdMediterranean/d+GdMediterranean/d+GdB. This finding suggests that in Sardinia the linkage between the two loci under consideration may be tighter than previously assumed.

Color Vision Defects↗
PubMed1977

Linkage disequilibrium for two X-linked genes in Sardinia and its bearing on the statistical mapping of the human X chromosome.

The distribution of four X-linked mutants (G6PD, Deutan, Protan and Xg) among lowland and once highly malarial populations of Sardinia discloses a clear-cut example of linkage disequiligrium between two of them (G6PD and Protan). In the same populations the distribution of G6PD-deficiency versus colorblindness of the Deutan type and the Xg blood-group is not significantly different from that expected at equilibrium. These data suggest indirectly that the loci for G6PD and Protan may be nearer to one another than those for G6PD and Deutan.

Blood Group Antigens↗