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F Cucca

Publications and source records attributed to F Cucca.

48 records · Page 3Linked to original sources
PubMed1995

The distribution of DR4 haplotypes in Sardinia suggests a primary association of type I diabetes with DRB1 and DQB1 loci.

The contribution of genetic variation at HLA class II loci to the susceptibility to and protection from IDDM was investigated by analyzing the distribution of HLA-DRB1*04 haplotypes in 630 Sardinian newborns and 155 Sardinian IDDM patients. The different RRs and ARs of the various DR4-DQB1*0302 haplotypes, significantly ranging from the strongly associated DRB1*0405, DQB1*0302 to the protective DRB1*0403, DQB1*0302 haplotypes, provides clearcut evidence that the DRB1 locus is crucial in conferring IDDM predisposition or protection. Also, the DQB1 locus influences IDDM predisposition or protection by restricting the disease-positive association to DRB1*0405 haplotypes carrying the susceptibility DQB1*0302 or DQB1*0201 alleles but not the protective DQB1*0301 allele. Haplotype analysis not only suggests that the DRB1 and DQB1 loci influence IDDM risk in the same way, but also that the HLA-linked protection is "dominant" compared with "susceptibility." These results, obtained from a population with one of the highest IDDM incidences in the world, define more clearly the contribution of the various HLA loci to IDDM protection or susceptibility and allow a more precise calculation of AR.

Adolescent↗
PubMed1995

Linkage disequilibrium mapping of a type 1 diabetes susceptibility gene (IDDM7) to chromosome 2q31-q33.

The role of human chromosome 2 in type 1 diabetes was evaluated by analysing linkage and linkage disequilibrium at 21 microsatellite marker loci, using 348 affected sibpair families and 107 simplex families. The microsatellite D2S152 was linked to, and associated with, disease in families from three different populations. Our evidence localizes a new diabetes susceptibility gene, IDDM7, to within two centiMorgans of D2S152. This places it in a region of chromosome 2q that shows conserved synteny with the region of mouse chromosome 1 containing the murine type 1 diabetes gene, Idd5. These results demonstrate the utility of polymorphic microsatellites for linkage disequilibrium mapping of genes for complex diseases.

Adolescent↗
PubMed1994

A gene dosage effect of the DQA1*0501/DQB1*0201 allelic combination influences the clinical heterogeneity of celiac disease.

This study reports the HLA-DR and DQ molecular characterization of 62 CD patients of Sardinian descent. Patients were divided in two groups (36 in group I and 26 in group II) according to the clinical features at the disease onset. Among the patients of group I, having the fully expressed form of CD and a mean age of 3 years at disease onset, a significant increase of DRB1*0301, DQA1*0501, DQB1*0201 homozygotes, encoding in cis two DQ (alpha 1*0501, beta 1*0201) susceptibility heterodimers, was observed when compared either with the patients of group II (pIII < 0.012) or with healthy individuals (pI < 10(-6)). On the other hand, in the patients of group II, presenting oligosymptomatic forms and a mean age of 5.7 years at the disease onset, the haplotype combinations encoding in cis or in trans only one DQ (alpha 1*0501, beta 1*0201) heterodimer were significantly increased in comparison either with the patients of group I (pIII < 0.026) or with controls (pII < 10(-6)). These findings suggest that a double dose of DQA1*0501, DQB1*0201 genes may predispose a person to an earlier onset and to more severe disease manifestations. Genotype analysis showed that only three patients (all in group I) failed to form in trans or in cis the DQ (alpha 1*0501, beta 1*0201) heterodimer and carried the DQA1*0101,DQB1*0501 haplotype, suggesting its possible role in CD susceptibility. In addition, a significant increment of DQB1*0501 gene (pc < 0.0065) was found comparing the frequency of DQB1 alleles in CD patients and healthy controls, after exclusion of DQB1*0201 chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

HLA-DQB1*0305 and -DQB1*0304 alleles among Sardinians. Evolutionary and practical implications for oligotyping.

This study, performed in individuals of Sardinian descent, reports an epidemiologic and molecular analysis of the recently identified DQB1*0304 and DQB1*0305 alleles. These two alleles having a gene frequency of 0.017 and 0.005, respectively, are not uncommon in Sardinia and are distributed fairly uniformly on the island. The analysis of DQB1 second and third exons of the two alleles revealed that although they have always been found included within the same DRB1*0403-DQA1*03 haplotype, they had a different origin. The sequence pattern of DQB1*0305 confirmed that it originated from the DQB1*0302 "recipient" gene by the insertion of a DQB1*0402 nucleotide stretch, within its beta-sheet region, while that of DQB1*0304 suggested that it originated from the DQB1*0301 gene, either by a single point mutation at codon 57 (GCC instead of GAC) or, alternatively, by a segmental transfer of a DQB1*0302 motif, including codon 57, within its alpha-helic region. Independently from the mechanism of generation, the fact that DQB1*0304 originated from DQB1*0301 allele was intriguing considering that, in over 1500 HLA class II Sardinian haplotypes examined, neither the putative parental DRB1*0403-DQA1*03-DQB1*0301 haplotypes were found. Finally, since the assignment of DQB1*0305 may be inaccurate with the traditional panel of probes commonly used for DQB1 oligotyping, the use of an additional oligonucleotide probe is recommended.

Alleles↗
PubMed1994

Insulin-dependent diabetes mellitus and the major histocompatibility complex peptide transporters TAP1 and TAP2: no association in a population with a high disease incidence.

Although many studies have established an association between insulin-dependent diabetes mellitus (IDDM) and the class II region of the human major histocompatibility complex (MHC), it has been difficult to assign susceptibility to a single locus. Recently, two antigen-processing genes, TAP1 and TAP2, have been identified within the region. Previous studies have reached conflicting conclusions as to the role of these genes in IDDM; it is uncertain whether an increased frequency of the allele TAP2A and a concomitant decrease in TAP2B are independent disease associations or secondary to linkage disequilibrium (LD) between TAP2A and HLA-DR3. To further investigate this question, we have characterized TAP1 and TAP2 alleles in 129 IDDM patients from Sardinia, a population with limited genetic heterogeneity and a high disease incidence. When compared to 90 random controls, the only significant difference was a decrease in the minor allele TAP2C in patients. However, when HLA-DR and -DQ matched controls were compared, this difference disappeared. Further analysis suggested that TAP2C was in LD with HLA-DRB1*1401 and subtypes of HLA-DRB1*11, alleles which were not observed in the IDDM population. LD was also observed between other TAP and HLA-DR alleles, in particular between TAP2A and HLA-DR3 in both patients and controls. Our data supports the conclusion that there is no primary association between TAP2 alleles and IDDM, and that previously reported associations may be due to LD with other class II loci.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Combinations of specific DRB1, DQA1, DQB1 haplotypes are associated with insulin-dependent diabetes mellitus in Sardinia.

The Sardinian population has an extremely high incidence of IDDM (30.2 of 100.000 in the age group of 0-14 years). This study reports the molecular characterization of HLA class II genes in 120 IDDM sporadic patients and 89 healthy subjects of Sardinian origin. Compared with other Caucasians, both Sardinian patients and controls had an unusual distribution of haplotypes and genotypes. In particular, there was a high gene frequency of the DRB1*0301, DQA1*0501, DQB1*0201 susceptibility haplotype both in patients (0.58) and controls (0.23) while a reduction of the DRB1*1501, DQA1*0102, DQB1*0602 protective haplotype (0.03) was observed in the healthy population. This distribution may partially explain the high incidence of IDDM reported in Sardinia. The analysis of the DQ beta 57 and DQ alpha 52 residues showed that the absence of Asp 57 and the presence of Arg 52 were associated with IDDM in a dose-response manner. On the other hand, we found that (a) a very similar distribution of these residues was found when comparing Sardinians with another healthy Caucasian population from the same latitude but with a lower rate of IDDM incidence; (b) several genotypes encoding the identical DQ alpha 52/DQ beta 57 phenotype carried very different relative risks; and (c) the DRB1*0403, DQA1*0301, DQB1*0304 haplotype (DQ beta 57 Asp-neg and DQ alpha 52 Arg-pos) was found in 40% of the DR4-positive controls but not in patients (p = 0.00034), while the DRB1*0405, DQA1*0301, and DQB1*0302 haplotype carrying the same residues at the same positions was found in 70% of the DR4-positive patients and in only one control (p = 0.00003). These findings suggest that IDDM susceptibility cannot be completely explained by the model in which only DQ alpha 52 and DQ beta 57 residues are taken into account.

Adolescent↗
PubMed1992

A high frequency of the A30, B18, DR3, DRw52, DQw2 extended haplotype in Sardinian celiac disease patients: further evidence that disease susceptibility is conferred by DQ A1*0501, B1*0201.

This study characterizes by serological and molecular methods the HLA class I and class II alleles in a group of celiac disease children, their parents and a control group of Sardinian descent. We found the DR3-DQw2 haplotype in all patients which was, in almost all cases (84%), associated with the HLA-A30, B18, DR3, DRw52, DQw2 extended haplotype named "Sardinian haplotype" because of its frequency (12-15%) in this Caucasian population. This is the first time that this DQw2-linked haplotype has been reported with such a high frequency in CD. However, no different distribution of "Sardinian haplotype" was found comparing CD patients with 91 haplotyped DQw2-positive controls. This finding indicates that the DQw2 antigen in Sardinians is almost always associated with the A30, B18, DR3, DRw52, DQw2 extended haplotype. The DQA1 and DQB1 second exon sequence analysis of the B18,DR3 and B8,DR3 haplotypes showed the DQA1*0501 and DQB1*0201 alleles which shared the already published sequences. DPB1 subtyping showed the DPB1*0301 allele more frequently (p less than 0.005) in CD patients but this difference was no longer significant when patients and controls, both heterozygous for the DR3-DQw2 haplotype, were compared. We suggest that the divergent HLA extended haplotypes and DP allele associated with CD, described in different Caucasian populations, can be explained by the particular DQw2 linkage disequilibrium in each population.

Adult↗
PubMed1992

The HLA DQB1*0502 allele is neutrally associated with insulin-dependent diabetes mellitus in the Sardinian population.

In the Sardinian population a very high incidence of insulin-dependent diabetes mellitus (IDDM) and the lack of HLA-DR2 protective effect due to the high frequency of the A2, Cw7, B17, 3F31, DR2, DQw1 extended haplotype has been reported. This haplotype, carrying a Serine at position 57 of the DQB1*0502 allele, has been previously reported to be underrepresented in patients when compared to controls. In order to provide an explanation for this finding, we defined by RFLP analysis the HLA haplotype of 45 Sardinian IDDM patients and 49 controls. All DR-2DQw1 subjects were molecularly characterized at the HLA DQA and DQB loci. All DR2-positive patients and the vast majority of the DR2-positive controls had the DQB1*0502 allele at the DR2-linked DQB1 locus, with no statistically significant difference between the two groups. All DQA1 genes were the ones expected, with only two exceptions. Nine out of 10 of the DR2-positive patients were compound heterozygotes for DQB1*0201/DQB1*0502 alleles; only this allele combination was significantly increased (p less than 0.0003). Our data suggests that a) the DQB1*0502 allele is neutral for IDDM development and b) the susceptibility to IDDM in our DR2-positive patients is related to the compound heterozygous state between the neutral DQA1*0102/DQB1*0502 and the susceptibility DQA1*0501/DQB1*0201 alleles.

Adolescent↗
PubMed1988

Deferoxamine-induced growth retardation in patients with thalassemia major.

In the retrospective study reported here, we compared the longitudinal growth in three groups of children with thalassemia major who received a similar transfusion program but different schedules of chelation treatment. In those patients who initiated deferoxamine (DF) administration by daily subcutaneous infusion (50 to 80 mg/kg/day) simultaneously with the beginning of transfusion (at 8 +/- 6 months), mean height at 2 to 6 years of age was significantly reduced in comparison (1) with those patients who initiated DF subcutaneous treatment after 3 years at similar doses and (2) with those who were treated intramuscularly with small doses. In the patients treated at an early stage, those with more marked stunted growth had a clinical and radiologic ricketslike syndrome associated with joint stiffness. Mineral metabolism studies in these patients showed a reduction of hair and leukocyte zinc levels and leukocyte alkaline phosphatase activity. Our findings indicate that DF administration at high doses by continuous infusion before iron overload has been established adversely affects longitudinal growth. By contrast, after 3 years of age, even large doses (in the order of 100/mg/kg/day) did not result in growth retardation. The growth retardation observed may be related to chelation of other trace elements, including zinc, in the presence of low iron burden, to the direct toxic effect of unchelated DF by interference with critical iron-dependent enzymes, or both. These results indicate that in patients with thalassemia major, DF administration should be initiated only after iron accumulation is established, namely, around 3 years of age, after 20 to 30 transfusions, which are usually associated with ferritin levels in the range of 800 to 1000 ng/ml. At this age, deferoxamine doses should be established on the basis of iron balance studies and dose response curves. Doses higher than 50 to 60 mg/kg do not adversely affect growth but produce toxic side effects on acoustic and visual pathways and therefore should not be used. Longitudinal growth monitoring of DF-treated patients is warranted.

Body Height↗
PubMedDate not supplied

No evidence for SEL1L as a candidate gene for IDDM11-conferred susceptibility.

BACKGROUND: The SEL1L gene is located on human chromosome 14q24.3-31 close to D14S67 which has been previously proposed to be a type 1 diabetes mellitus locus (IDDM11). Sel-1 is a negative regulator of the Notch signalling pathway and SEL1L is selectively expressed in adult pancreas and islets of Langerhans. This suggests that SEL1L may be a candidate gene for IDDM11. METHODS: We have analysed two newly identified CA-repeat polymorphisms within the genomic sequence of the SEL1L locus for association with type 1 diabetes mellitus (T1DM) in 152 Danish T1DM-affected sib-pair families and in 240 Sardinian families (229 simplex and 11 sib-pair families). RESULTS: No evidence for association of the two SEL1L markers with T1DM was observed in either the Danish or the Sardinian families. We have also used allelic sharing methods to analyse linkage with T1DM in the IDDM11 region using the same markers and the Danish collection of affected sib-pair families. No evidence of linkage was observed (Z(max)=0.86). CONCLUSION: Although several lines of evidence suggest that SEL1L might be a candidate for IDDM11-conferred susceptibility to T1DM the present study does not support this hypothesis.

Alleles↗