Biomedical subjects

Emanuela Medda

Publications and source records attributed to Emanuela Medda.

6 recordsLinked to original sources

PubMed2006

[Statistical methods for the analysis of twin data].

The most important statistical methods currently used for the analysis of twin data are described. The main objective of these methods is to estimate the contribution of the genetic and environmental factors to the variability of normal or pathological human traits, by means of the information obtained from monozygotic and dizygotic twin pairs. In this context, the concept of heritability becomes relevant. Not only the simple comparison between monozygotic and dizygotic twins, based on measures such as the concordance and the correlation, but also new and more complex approaches are presented, with a special emphasis on the structural equation models, and a synthetic view on the DF-analysis and the correlated frailty models. Some examples of applications to the data of the Italian Twin Registry are also illustrated.

Data Interpretation, Statistical↗

PubMed2005

An association analysis of microsatellite markers across the Prader-Willi/Angelman critical region on chromosome 15 (q11-13) and autism spectrum disorder.

Autism (OMIM 209850) is a neurodevelopmental disorder with a significant genetic component of a complex nature. Cytogenetic abnormalities in the Prader-Willi/Angelman syndrome critical region (PWACR) on chromosome 15 (q11-13) have been described in several individuals with autism. We have examined five microsatellite markers spread across the 4 Mb PWACR for linkage disequilibrium (LD) in 148 families with autism spectrum disorder (ASD) and a subset of 82 families with autism using the extended transmission disequilibrium test (ETDT). The markers examined were D15S11, D15S128, D15S1506, GABRB3, and D15S1002. In addition we have examined the microsatellite D15S822 for hemizygous deletion status in our sample as it had been previously reported to be increased in autism. We found no significant LD with any of the markers tested either in the ASD or autism families when looking at paternal and maternal meioses combined. However, as there are known imprinted genes in the region, including possibly GABRB3, we also examined for LD in paternal and maternal meioses separately. Examining paternal transmissions only, we found marginal evidence for LD with a protective allele at marker D15S11 in the ASD families (Chi-sq 7 df, P = 0.05) and marginal evidence for risk alleles at markers D15S1506 (Chi-sq 13.7, 6 df, P = 0.06), GABRB3 (Chi-sq 15.9, 8 df, P = 0.11) and D15S1002 (Chi-sq 17.7, 9 df, P = 0.08) in the autism only families. The allele responsible for the association with GABRB3 is the 191 allele which was previously reported to be overtransmitted. Hemizygous deletion of the microsatellite D15S822 was found in 3 out of 340 independent chromosomes in our sample; a rate of 0.8%. This is not significantly different to the frequency in the general population. In conclusion, our results did not rule out the involvement of this chromosomal region, but provided further evidence, albeit very limited, to implicate GABRB3. Further more systematic work in larger samples is required and confirmation that GABRB3 is imprinted is desirable.

Alleles↗

PubMed2005

Risk factors for congenital hypothyroidism: results of a population case-control study (1997-2003).

OBJECTIVE: To identify risk factors for permanent and transient congenital hypothyroidism (CH). DESIGN: A population-based case-control study was carried out by using the network created in Italy for the National Register of Infants with CH. METHODS: Four controls were enrolled for each new CH infant; 173 cases and 690 controls were enrolled in 4 years. In order to distinguish among risk factors for permanent and transient CH, diagnosis was re-evaluated 3 years after enrollment when there was a suspicion of transient CH being present. Familial, maternal, neonatal and environmental influences were investigated. RESULTS: An increased risk for permanent CH was detected in twins by a multivariate analysis (odds ratio (OR) = 12.2, 95% confidence interval (CI): 2.4-62.3). A statistically significant association with additional birth defects, female gender and gestational age >40 weeks was also confirmed. Although not significant, an increased risk of CH was observed among infants with a family history of thyroid diseases among parents (OR = 1.9, 95% CI: 0.7-5.2). Maternal diabetes was also found to be slightly associated with permanent CH (OR = 15.7, 95% CI: 0.9-523) in infants who were large for gestational age. With regard to transient CH, intrauterine growth retardation and preterm delivery were independent risk factors for this form of CH. CONCLUSION: This study showed that many risk factors contribute to the aetiology of CH. In particular, our results suggested a multifactorial origin of CH in which genetic and environmental factors play a role in the development of the disease.

Adult↗

PubMed2005

Correlation between metal ions and clinical findings in subjects affected by Alzheimer's disease.

There is a growing interest to evaluate metals in biological fluids in Alzheimer's disease (AD). There are numerous studies on this theme, but just few papers analyzed the relationship between haematic metal concentrations and the clinical features of the disease. In this study, possible associations between clinical features of AD and the variations in serum and blood concentration of some metals, as well as the serum oxidative status and the antioxidant capacity have been investigated. Sixty subjects with AD were enrolled. Some elements correlated with gender, depression and duration of the disease. However, the most significant result was the relationship between blood Ca and Fe levels and the severity of cognitive impairment. We hypothesize that Ca and Fe might play an important role in the pathogenetic mechanisms of AD.

Aged↗

PubMed2003

Genetic amniocentesis: a risk factor for preterm delivery?

OBJECTIVE: To determine whether genetic amniocentesis performed in the second trimester of pregnancy is associated with the risk of preterm delivery. STUDY DESIGN: Case-control study performed in several departments of obstetrics and gynaecology of nine European countries. Three thousand and ninety-one preterm births and 5298 controls randomly selected from singleton births born at term during 1994-1997 were analysed. Logistic regression models were used to compare preterm births altogether and, separately, spontaneous preterm delivery and induced preterm delivery. RESULTS: An increased risk of preterm delivery was found in women having second trimester genetic amniocentesis after taking account of other risk factors and confounding variables (odds ratios (OR)=1.59, 95% confidence intervals (95% CI): 1.31-1.92). The association was statistically significant and similar for spontaneous preterm delivery and induced preterm delivery. CONCLUSION: The study shows an association between preterm delivery and genetic amniocentesis. In view of the wide use of amniocentesis, further research on the etiologic role of this prenatal diagnostic technique is needed.

Adult↗

PubMed2002

[Reproductive health of immigrant women in the Lazio region of Italy].

The number of legal immigrant women living in the Lazio region of Italy has increased in recent years; there were 69,320 "permessi di soggiorno" (temporary residence permits) issued in 1992 but 119,778 issued in 2000. This analysis concerns women who left hospital after having a live birth, an induced abortion or a spontaneous abortion. The foreign women were compared with all (Italian and foreign) women living in Lazio. The general fertility rate is slightly higher among all women resident in Lazio than among the foreign women, but the latter have a higher rate at ages 18-24 years. The risk of induced abortion is higher (34.8/1000 women) among the foreigners than among all residents (10.5/1000 women). The spontaneous abortion ratio was also higher among the foreigners (213.8/1000 live births) than the residents (154.6/1000 live births). There is clear evidence of an increase in the demand from foreign women for medical services for reasons associated with reproduction. The provision of these services needs to be modified to take account of their particular needs.

Abortion, Induced↗