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G Monni

Publications and source records attributed to G Monni.

At least 55 records · Page 3Linked to original sources
PubMed1990

Antenatal diagnosis of beta-thalassemia in Sardinia.

This paper reviews the characteristics and the results of 15 years of experience with a preventive program, based on carrier screening and prenatal diagnosis, designed to control thalassemia major in the Sardinian population. The education of the population about thalassemia and the modalities for its prevention was accomplished via the mass media. Carrier screening was carried out voluntarily on couples of child-bearing age. Prenatal diagnosis was initially carried out by fetal blood analysis; since 1983, it has been done by DNA analysis on non-amplified or amplified DNA. Different chorionic villous sampling procedures have been used. Nowadays, we have adopted the transabdominal approach because, in our experience, it seems to be associated with a low risk (2%) of fetal mortality. At the present time, the beta-thalassemia mutations are detected directly by dot-blot analysis of amplified DNA with 32P- or horseradish peroxidase-labeled allele-specific oligonucleotide probes. Two oligonucleotide probes, one complementary to the codon-39 nonsense mutation, which accounts for 95.7% of the beta-thalassemia chromosomes in the Sardinian population, and the other complementary to the frameshift at codon 6, which is the second most common mutation in our population (2.1%), allow us to make prenatal diagnosis in the large majority of cases. Notwithstanding a careful dissection of maternal decidua from chorionic villi, co-amplification of maternal sequence was detected in 4 out of 425 cases tested by this procedure. In order to avoid this pitfall, the simultaneous amplification of highly polymorphic VNTR (variable number of tandem repeats) segments could be used. On the whole we have so far carried out 2711 prenatal tests: 1130 by fetal blood analysis, 1156 by oligonucleotide hybridization on electrophoretically separated DNA fragments, and 425 by dot-blot analysis on amplified DNA with allele-specific oligonucleotide probes. Two errors occurred by fetal blood analysis and none by DNA analysis. The incidence of thalassemia major declined from 1:250 live births in the absence of prevention to 1:1000 after the establishment of this program, indicating that carrier screening and prenatal diagnosis are effective means for preventing thalassemia major at the population level.

Female↗
PubMed1990

Reliability of prenatal diagnosis of genetic diseases by analysis of amplified trophoblast DNA.

Dot blot analysis on enzymatically amplified trophoblast DNA with allele specific oligonucleotide probes is currently used for the prenatal diagnosis of single gene disorders characterised at the molecular level, such as the beta thalassaemias, phenylketonuria, sickle cell anaemia, and alpha 1-anti-trypsin deficiency. A potential problem with the use of this procedure is the co-amplification of maternal sequences, which may obscure the diagnosis in the fetus. To address this question, we carried out prenatal diagnosis of beta thalassaemia in 300 couples at risk by dot blot analysis on enzymatically amplified DNA with 32P or horseradish peroxidase labelled allele specific oligonucleotide probes. We verified the diagnosis obtained by this procedure with oligonucleotide hybridisation on electrophoretically separated non-amplified trophoblast DNA fragments. We detected no co-amplified maternal sequences, even with a faint signal, in the dot blot of trophoblast DNA from those fetuses diagnosed as normal or homozygotes, nor in those diagnosed as heterozygotes, who were born to parents carrying different mutations and had inherited the paternal mutation. These results indicate that, when careful dissection of trophoblast tissue from maternal decidua is carried out, amplification of chorionic villi DNA is not associated with amplification of maternal DNA sequences. We may thus conclude that dot blot analysis of trophoblast DNA is a very reliable procedure for prenatal diagnosis.

Chorionic Villi Sampling↗
PubMed1989

Prenatal diagnosis of beta-thalassaemia in Mediterranean populations by dot blot analysis with DNA amplification and allele specific oligonucleotide probes.

In this study, we describe a simple strategy to detect beta-thalassaemia mutations in prospective parents and to make prenatal diagnosis in pregnancies at risk in the Mediterranean population. Screening of prospective parents is carried out by dot blot analysis on enzymatically amplified DNA with a set of oligonucleotide probes complementary to the most common mutations in this population. Prenatal diagnosis is accomplished by the same procedure on enzymatically amplified amniocyte or trophoblast DNA. The main advantages of this procedure are the simplicity, sensitivity (0.05 micrograms of DNA), and rapidity (12-24 h). Further simplification is obtained by amplification of the DNA from crude amniotic cell lysate. The very low amount of fetal material necessary for this analysis eliminates the need to culture amniotic fluid cells and may decrease the fetal loss rate associated with trophoblast sampling. The number of specific DNA sequences obtained by the amplification procedure allowed us to use non-radioactive labelled oligonucleotide probes, which have several advantages compared to radioactive probes.

Alleles↗
PubMed1989

The prevention of thalassemia in Sardinia.

In this paper we review the characteristics and effectiveness of a program aimed at preventing homozygous beta-thalassemia in the Sardinian population. The target population for screening were couples at marriage, conception or early pregnancy. Awareness of the problem and the involvement of the population were achieved via the mass media or by personal approaches through lectures or discussions. Parents' Associations were consulted and have made themselves available to prospective couples in several critical areas. Education on thalassemias was introduced into the school curriculum. Counseling was based on private interviews at which the several options available were discussed with the individual carrier or the couples. Prenatal diagnosis was chosen by the large majority of couples counseled. The introduction of 1st trimester diagnosis resulted in a striking increase of the acceptance rate from 93.2 to 99.1%. Prenatal diagnosis was carried out initially by fetal blood analysis and thereafter by trophoblast or amniocyte DNA analysis. Direct detection of the mutation by oligonucleotide hybridization on agarose gel separated DNA fragments or by dot-blot analysis with allelic specific oligonucleotide probes on enzymatically amplified DNA was used. This program resulted in a decline in thalassemia major births of 90%. The reasons for residual cases were mostly lack of information and, less frequently, misdiagnoses or refusal of fetal diagnosis.

Adult↗
PubMed1988

Problems in prenatal diagnosis of beta-thalassaemia by fetal blood analysis: beta-chain variant comigrating with gamma chains.

This report describes a couple at risk for beta-thalassaemia in which one spouse was heterozygous for classical high Hb A2 beta-thalassaemia while the other had the compound heterozygous state for beta+-thalassaemia and a beta-chain variant. This variant comigrates on carboxymethyl-cellulose columns (CMC) with gamma-chains, indicating that globin separation on CMC columns could not have been used for fetal diagnosis. The beta-chain variant migrates separately from the other globin chains on HPLC and the respective abnormal haemoglobin can be separated by isoelectrofocusing. Oligonucleotide hybridization showed that both parents were carriers of the beta+ IVS-1, nt 6 mutation. Prenatal diagnosis was successfully accomplished by oligonucleotide analysis on trophoblast DNA. This case indicates that an Antenatal Service should have alternative methods to CMC columns so as to carry out prenatal diagnosis of beta-thalassaemia in uncommon cases.

Blood Protein Electrophoresis↗
PubMed1988

Prenatal diagnosis of beta-thalassaemia by second-trimester chorionic villus sampling.

In this study we evaluated the feasibility of second-trimester transabdominal chorionic villus sampling for prenatal diagnosis of beta-thalassaemia in 80 pregnancies at risk presenting in the second trimester at the Antenatal Service. Sampling was carried out from 13 to 20 weeks and was successful in all cases. The amount of chorionic villi obtained varied from 10 to 40 mg, which was sufficient to make fetal diagnosis by oligonucleotide analysis within 10 days from sampling in all cases. No fetal losses occurred. From these results we conclude that transabdominal chorionic villus sampling is a useful procedure for prenatal diagnosis of beta-thalassaemia in those couples presenting after the first trimester.

Biopsy, Needle↗
PubMed1988

Prenatal diagnosis of beta thalassaemia by oligonucleotide analysis in Mediterranean populations.

We have used four oligonucleotide probes and two restriction enzymes to detect the beta thalassaemia mutation in a group of 61 couples of Italian descent who were prospective parents. We have been able to define the beta thalassaemia mutation in both parents in 47 couples and in only one parent in 12 couples. Prenatal diagnosis was accomplished successfully either by amniocyte (two) or trophoblast (26) DNA analysis in 28 couples in which the pregnancy was in progress. These results indicate that direct identification of the mutation by oligonucleotide or restriction endonuclease analysis is a practical and useful method for prenatal diagnosis of beta thalassaemia in childless couples.

Amniocentesis↗
PubMed1987

Chorionic villus sampling and acceptance rate of prenatal diagnosis.

In this paper, we compared the acceptance rate of fetal diagnosis for beta-thalassemia in three group of couples of Sardinian descent; the first counselled before DNA analysis was available, the second presenting after DNA analysis was introduced but too late for chorionic villus sampling and thus monitored by amniocyte DNA analysis and the third presenting within the first trimester after DNA analysis was introduced and thus in time for trophoblast DNA analysis. A higher proportion of couples from the latter group opted for fetal testing as compared to the 1st and 2nd group. These results indicate that in this population, introduction of 1st trimester diagnosis made prenatal testing acceptable to practically all counselled couples at risk.

Adult↗
PubMed1987

Chorionic villus sampling by rigid forceps: experience with 300 cases at risk for thalassemia major.

In this article we report the results of chorionic villus sampling by a biopsy forceps inserted via the cervix under ultrasonic guidance in 300 pregnancies at risk for thalassemia major. A sufficient amount of chorionic villi for deoxyribonucleic acid analysis by oligonucleotide hybridization was obtained in all cases tested but one, with a success rate of 99.7%. The percentage of fetal loss, expressed as proportion of continuing pregnancies, was 4.8%. To verify the results, we carried out amniocyte deoxyribonucleic acid analysis in all the continuing pregnancies for the first 100 cases and in those in which trophoblast deoxyribonucleic acid analysis showed the heterozygous state for beta-thalassemia for the second 200 cases. At the beginning we had two cases of decidual contamination in such an amount to cause misdiagnosis. Successively more careful elimination of decidual tissue from villi avoided avoided this pitfall. These results indicate that chorionic villus sampling by a rigid forceps is a reliable and relatively safe method for fetal diagnosis of genetic diseases by deoxyribonucleic acid analysis.

Biopsy↗
PubMed1985

Prenatal diagnosis of beta-thalassaemia with the synthetic-oligomer technique.

103 couples attending the antenatal clinic in Sardinia were screened for the beta o-39 (nonsense) mutation, which codes for beta-thalassaemia, with the oligonucleotide method. In 94 couples both members had the beta o-39 mutant and thus were eligible for antenatal testing with this method. These pregnancies were monitored with amniocentesis (61) or trophoblast biopsy (33). Prenatal diagnosis in those monitored with amniocentesis was carried out with DNA analysis of uncultivated amniocytes (19) or cultivated cells (38). In 4 pregnancies results were unsatisfactory, and prenatal diagnosis was repeated with fetal-blood analysis. Trophoblast biopsy was unsuccessful in 1 pregnancy and gave a misdiagnosis in another because of maternal contamination. In the latter case the genotype of the fetus was established with amniocyte DNA analysis and globin-chain-synthesis studies.

Amnion↗
PubMed1985

Antenatal diagnosis of thalassemia major in Sardinia.

In this report, we summarized our experience, carried out in Sardinia, with antenatal diagnosis in one thousand pregnancies in which the fetus was at risk for homozygous beta-thalassemia. In the majority of these cases, the thalassemia lesion segregating in the family was the nonsense mutation at the codon corresponding to amino-acid 39. At the outset (976 cases) we used globin chain synthesis analysis by column chromatography on fetal blood obtained by placental aspiration, and recently (24 cases) we employed the synthetic oligonucleotide method on amniocyte DNA. Apart from 126 pregnancies still in progress, in all the other cases the diagnosis has been confirmed. In the majority of the cases (99%), we obtained sufficient fetal blood for the analysis. The fetal mortality associated with placental aspiration was 6.1%. The biochemical analysis gave reliable results. We had two misdiagnoses (0.2%): one due to a nonglobin protein comigrating with the beta chains and the other for a misclassification of the type of thalassemia segregating in the family. The oligonucleotide method gave clear-cut results in all the cases tested. The method was sensitive enough to detect the mutation directly in the DNA isolated from 20-25 ml of amniotic fluid in 75% of the pregnancies tested. In one case, we successfully employed this method for the analysis of the DNA isolated from chorionic villi. The oligonucleotide method seems to be the best procedure for monitoring the pregnancies at risk for beta-thalassemia in places where one or a few beta-thalassemia lesions are prevalent.

Amnion↗
PubMedDate not supplied

Prenatal diagnosis of the fragile-X in male monozygotic twins: discordant expression of the fragile site in amniocytes.

A prenatal diagnosis of the fragile-X syndrome in monozygotic male twins is reported. The expression of the fragile site was discordant in amniotic cells. Fetal blood and, after therapeutic abortion, skin fibroblasts were positive in both fetuses. Our data suggest that great care should be taken when using amniocytes for prenatal diagnosis of the fragile-X syndrome.

Adult↗
PubMedDate not supplied

First trimester diagnosis of beta-thalassaemia in a twin pregnancy.

This paper reports the results of first trimester prenatal diagnosis in a twin pregnancy at risk for homozygous beta 0-thalassaemia (beta 0-39 mutant). Trophoblast samples from both twins were obtained at 10 weeks gestation with a forceps guided by ultrasound. Trophoblast DNA analysis, carried out with the oligonucleotide technique, revealed that one fetus was homozygous and the other heterozygous for the beta-39 mutant. This diagnosis was confirmed at 17 weeks gestation by amniocyte DNA analysis. DNA polymorphism analysis within the alpha-globin gene provided useful genetic markers for twin differentiation.

Chromosome Mapping↗
PubMedDate not supplied

Prenatal diagnosis of thalassemia major by fetal blood analysis: experience with 1000 cases.

In this report we have summarized our experience with the prenatal diagnosis of beta-thalassemia in 1000 pregnancies followed at least until 12 months after birth. In the majority of these cases, the thalassemia lesion was the nonsense mutation at the codon corresponding to amino acid 39, which produces the hematological phenotype of beta o-thalassemia. Fetal blood sampling was carried out by placental aspiration, by which a sufficient amount of fetal blood for analysis was obtained in the majority of cases (99 per cent). The fetal mortality associated with fetal blood sampling was 6.3 per cent. Those placental samples contaminated by maternal cells were successfully purified by Orskov lysis. Fetal blood was analysed by globin chain synthesis on CM-52 columns, which gave reliable results. Two misdiagnoses (0.2 per cent) have been made of which one was due to a non-globin protein co-migrating with the beta-chains while the other resulted from a misclassification of the type of thalassemia segregating in the family.

Blood Specimen Collection↗
PubMedDate not supplied

Assessment of risk for chromosomal abnormalities at 10-14 weeks of gestation by nuchal translucency and maternal age in 5,210 fetuses at a single centre.

OBJECTIVE: To evaluate the screening of chromosomal abnormalities by nuchal translucency (NT) measurement. METHODS: Assessment of risk for chromosomal abnormalities by NT and maternal age in 5,210 single fetuses with karyotype and outcome already known. RESULTS: Risk was > or =1 in 300 in 640 (12.2%) of all fetuses, in 575 (11.1%) of the normal fetuses, in 38 (80.8%) of the fetuses affected by trisomy 21, and in 65 (89%) of the fetuses affected by chromosomal abnormalities. Risk was > or =1 in 200 in 477 (9.1%) of all fetuses, in 418 (8.1%) of the normal fetuses, in 35 (74.4%) of the fetuses affected by trisomy 21, and in 59 (80.8%) of the fetuses affected by chromosomal abnormalities. Risk was > or =1 in 100 in 270 (5.1%) of all fetuses, in 216 (4.2%) of the normal fetuses, in 33 (70.2%) of the fetuses affected by trisomy 21, and in 54 (73.9%) of the fetuses affected by chromosomal abnormalities. CONCLUSIONS: Risk generated by NT and maternal age is effective in screening for chromosomal abnormalities.

Adult↗