S. De Virgiliis

Existence of a genetic risk factor on chromosome 5q in Italian Coeliac Disease families

Coeliac disease (CD) is a malabsorptive disorder of the small intestine resulting from ingestion of gluten. The HLA risk factors involved in CD are well known but do not explain the whole genetic susceptibility. Several regions of potential linkage on chromosomes 3q, 5q, 10q, 11q, 15q and 19q have already been reported in the literature. These six regions were analyzed with the Maximum Lod Score method on a dense set of markers. A new sample of 89 Italian sibpairs was available for study. There was no evidence for linkage for any of the regions tested, except for chromosome 5q. For this region, our data, as well as a sample of 93 sibpairs from our first genome screen (Greco et al. 1998), are compatible with the presence of a risk factor for CD with a moderate effect.

Enterocyte actin autoantibody detection: a new diagnostic tool in celiac disease diagnosis: results of a multicenter study.

OBJECTIVES:This study describes a new method to detect autoantibodies against actin filaments (AAA) as a serological marker of intestinal villous atrophy (IVA) in celiac disease (CD), and reports the results of an Italian double-blind multicenter study.METHODS:IgA-AAA were analyzed by immunofluorescence using a newly developed method based on intestinal epithelial cells cultured in presence of colchicine. IgA-AAA were blindly evaluated prospectively in 223 antiendomysial antibody (AEA) and/or antitransglutaminase antibody (TGA) positive subjects and in 78 AEA and TGA negative subjects. IgA-AAA positive patients underwent an intestinal biopsy to confirm the diagnosis. Moreover, IgA-AAA were retrospectively investigated in 84 biopsy-proven CD patients and in 2,000 new consecutively collected serum samples from AEA and TGA negative nonbiopsied subjects.RESULTS:IgA-AAA were positive in 98.2% of the CD patients with flat mucosa, in 89% with subtotal villous atrophy, and in 30% with partial villous atrophy. IgA-AAA were present in none of the AEA and TGA negative nonbiopsied controls. In AEA and/or TGA positive CD patients IgA-AAA positivity significantly correlated with IVA (p < 0.000 in the prospective study, p= 0.005 in the retrospective study). In the prospective study, the values of sensitivity, specificity, the positive predictive value, the negative predictive value, and the efficiency of the IgA-AAA test to identify patients with IVA were, respectively, 83.9%, 95.1%, 97.8%, 69.2%, and 87.0%. Furthermore, a significant correlation (p < 0.0001) was found between the IgA-AAA serum titre and the degree of IVA (rs 0.56).CONCLUSIONS:The results of this multicenter study show that the new method for IgA-AAA detection could represent a practical diagnostic tool in AEA and/or TGA positive subjects, which would be especially useful when IVA shows a patchy distribution, when the histological picture is difficult to interpret, or when a biopsy could represent a life-threatening risk.

Iron overload and desferrioxamine chelation therapy in β-thalassemia intermedia

This study on serum ferritin levels ind urinary iron excretion after 12h subcutaneous infusion of desferrioxamine in 10 thalassemia intermedia patients shows that even nontransfusion-dependent patients may have positive iron balance resulting in iron overload from 5 years of age. However, the iron overload found in these patients appears to be much lower than in age matched patients with transfusion-dependent thalassemia major. Iron overload increases with advancing age, as shown by increasing serum ferritin levels and desferrioxamine-induced urinary iron elimination. After a six month trial of 12h continuous subcutaneous desferrioxamine administration there was a significant decline in serum ferritin levels.From this study it seems that iron chelation is indicated in thalassemia intermedia patients over 5 years of age in order to prevent iron accumulation. However, the appropriate treatment schedule should be tailored to the individual needs of each patients, established by close monitoring of serum ferritin levels and desferrioxamine-induced urinary iron elimination.

Auditory Involvement in Thalassemia Major

The auditory function of 75 children affected by homozygous beta0-thalassemia, managed with a low transfusion scheme and treated irregularly with low doses of desferrioxamine, and of 75 controls were examined. In 12 patients a mild bilateral conductive hearing impairment due to bony hypertrophy and/or adenoid hypertrophy was found. In 43 cases a moderate monolateral or bilateral sensory-neural hearing loss at high frequencies with recruitment phenomenon was observed. Ferritin levels were determined in a randomly chosen group of these patients with (14) and without heaing loss (11). In the subjects with sensory-neural hearing loss the mean ferritin levels were significantly higher than in those with no hearing defect. There was no obvious relation between sensory-neural damage on the one hand and Hb levels and unit of blood transfused on the other. The results of this study suggest that iron overload could be a cause of damage in the high frequency elements of the auditory mechanism. Intermittent hypoxia and slow 8th nerve compression due to bony hypertrophy as causes of auditory involvement are also discussed.

Genetic testing improves the diagnosis of adult type hypolactasia in the Mediterranean population of Sardinia

Objective:Recently, the C/T-13910 polymorphism on chromosome 2q21 in North-European populations has been found completely associated with lactase activity and its genetic typing proposed as first-stage screening test for adult hypolactasia. However, the C/T-13910 variant in some sub-Saharan African groups is not a predictor of lactase persistence. In this work, we wanted to verify if in the Mediterranean island of Sardinia, located in Southern Europe, the C/T-13910 polymorphism may be useful or not for the diagnosis of adult type hypolactasia.Design:Validation study of a genetic testing for adult type hypolactasia in Sardinians.Setting:Brotzu Hospital and Microcitemico Hospital, Cagliari, Italy.Subjects:The sample consisted in 84 Sardinian individuals (63 women and 21 men; range 20–73 years) selected from a group of 832 patients.Methods:Genetic testing was compared to an improved test obtained by a combination of different breath hydrogen tests and clinical assessment.Results:We found that all 49 individuals with lactose malabsorption, demonstrated by a combination of different breath hydrogen tests and clinical assessment, carried the C/C-13910 genotype associated with lactase non-persistence, 23 individuals with lactose normal absorption carried the C/T-13910 genotype associated with lactase persistence and only one person with the above phenotype showed a discordant C/C-13910 genotype. The genetic testing showed very high sensitivity, specificity, positive and negative predictive values of 100, 95.8, 98 and 100%, respectively.Conclusions:Sardinians, unlike some ethnic groups in sub-Saharan Africa, show the same genetic association of hypolactasia with the C/T-13910 variant as other North-European populations. The genetic testing for the C/T-13910 variant may contribute to improving the diagnosis of adult type hypolactasia.

Saturation of the 5q31-q33 Candidate Region for Coeliac Disease

The first genome wide screening performed on Italian affected sib‐pair families ( Greco et al. 1998 ) gave evidence for linkage with coeliac disease in the 5q region. This finding was replicated in a second independent dataset ( Greco et al. 2001 ). Overall, pooling both samples, the highest MLS value (2.92) was found for the most centromeric marker tested, D5S640. In the present study, the 5q31‐q33 region was saturated with 12 new markers around D5S640, in order to verify whether there would be a shift of the MLS position. This study allowed us to support our previous finding of linkage for the region 5q31‐q33, with the most significant MLS value at D5S2014, very close to the marker D5S640. No evidence for interaction between this risk factor and the one in the HLA region was found. Furthermore, many different groups have independently obtained analogous results for this region, confirming the presence of a susceptibility locus in the region 5q31‐q33. This region contains several interesting candidate genes for coeliac disease.

Agenesis of the corpus callosum, infantile spasms, spastic quadriplegia, microcephaly and severe mental retardation in three siblings

A sibship consisting of three siblings, one male and two females with unrelated parents, showed a clinical syndrome including: infantile spasms with hypsarrhythmia, microcephaly, severe mental retardation and spastic quadriplegia. The pneumoencephalogram performed in two sibs showed agenesis of the corpus callosum and aqueductal stenosis with tri‐ventricular dilatation. The disorder did not show a progressive course with deterioration of mental and neurologic functions. No biochemical or cytogenetic defect could be identified. Complement fixation for cytomegalovirus was negative. This syndrome complex is probably inherited as an autosomal recessive trait. The clinical and the genetic aspects of the syndrome are discussed.

Chronic Liver Disease in Transfusion-Dependent Thalassemia: Liver Iron Quantitation and Distribution

The quantitative and/or qualitative distribution of liver iron was assessed in 81 transfusion-dependent thalassemia major patients with chronic liver disease (36 with chronic active hepatitis, 23 with chronic persistent hepatitis, 22 with siderosis). Viral marker studies showed only 3 cases with both HBsAg and anti-HBc positivity in the serum, while the others had anti-HBc and anti-HBs or only anti-HBs or no B viral markers. A significantly higher iron overload was found in chronic hepatitis, particularly chronic active hepatitis, than in siderosis. The increased iron overload may be due to less intensive chelation treatment, higher intestinal absorption secondary to lower mean Hb levels, and/or to liver inflammation-dependent iron deposition. The liver iron overload in turn amy facilitate the development or persistence of chronic progressive liver disease.

Interaction between the glucose-6-phosphate dehydrogenase deficiency and thalassaemia genes at phenotype level.

Summary. No significant differences were observed in the mean values of Hb A2 levels and red cell indices between G6PD‐ and G6PD+β thalassaemia carriers apart from the MCV, which was significantly higher in β thalassaemia G6PD‐ subjects, but still in the thalassaemia carrier range. No difference was seen between G6PD+ and G6PD‐α thalassaemia carriers. G6PD+β thalassaemia carriers show a significant increase in G6PD levels expressed as activity per g of Hb and to lesser extent as activity per number of red cells x 109; in G6PD+α thalassaemia carriers this increase is statistically significant only when the enzyme levels are expressed as activity per g of Hb. G6PD‐β thalassaemia carriers had enzyme levels higher than non‐thalassaemic G6PD‐ subjects only when the activity is expressed per g of Hb. G6PD activity was found to be increased in G6PD+ and G6PD‐ Hb H disease patients.

Early and severe neurological features in a Wilson disease patient compound heterozygous for two frameshift mutations

Abstract We describe a patient with Wilson disease who presented at 11 years of age with neurological symptoms and subsequent rapid progression of neurological impairment but absent hepatic manifestations. Molecular analysis showed compound heterozygosity for two frameshift mutations, 2299insC and 214delAT, which most likely result in an absent or inactive protein product. Mutation-phenotypic analysis indicates that this genotype does not explain the severe phenotype, suggesting the presence of modifying factors. Conclusion Wilson disease may present even in childhood or adolescence with neurological abnormalities in the absence of hepatic manifestations.