HLA Class II Alleles Susceptibility Markers of Type 1 Diabetes Fail to Specify Phenotypes of Ketosis-Prone Diabetes in Adult Tunisian Patients

We aimed to characterize the different subgroups of ketosis-prone diabetes (KPD) in a sample of Tunisian patients using the Aβ scheme based on the presence or absence of β-cell autoantibodies (A+ or A−) and β-cell functional reserve (β+ or β−) and we investigated whether HLA class II alleles could contribute to distinct KPD phenotypes. We enrolled 43 adult patients with a first episode of ketosis. For all patients we evaluated clinical parameters, β-cell autoimmunity, β-cell function and HLA class II alleles. Frequency distribution of the 4 subgroups was 23.3% A+β−, 23.3% A−β−, 11.6% A+β+ and 41.9% A−β+. Patients from the group A+β− were significantly younger than those from the group A−β− (P = .002). HLA susceptibility markers were significantly more frequent in patients with autoantibodies (P = .003). These patients also had resistance alleles but they were more frequent in A+β+ than A+β− patients (P = .04). Insulin requirement was not associated to the presence or the absence of HLA susceptibility markers. HLA class II alleles associated with susceptibility to autoimmune diabetes have not allowed us to further define Tunisian KPD groups. However, high prevalence of HLA resistance alleles in our patients may reflect a particular genetic background of Tunisian KPD population

Genetic analysis of Turner syndrome in Tunisian patients: from diagnosis to management

Background/aim Turner syndrome (TS) is a rare sex chromosome abnormality in women, occurring in approximately one in 2500 live births, associated with a wide range of clinical stigmata of which short stature, ovarian dysgenesis, and dysmorphic features are the most frequent. Morbidity and mortality are clearly increased compared with the general population, and the average age at diagnosis is quite delayed. Even if the majority of females with TS have a non-mosaic 45,X karyotype, several karyotype variations exist, including short or long arm deletion, ring X isochromosome of the long arm, and 45,X 46,XX mosaicism. This explains the large phenotypic and genetic heterogeneities of TS, which make the diagnosis and especially the management increasingly difficult. We present in this work a genetic study of TS in the Tunisian population to establish a genotype–phenotype correlation, which would be of great help for the diagnosis and the care of patients. Patients and methods A total of 26 unrelated Tunisian girls were included in this study. All patients underwent a complete clinical and biochemical examination as well as karyotyping. The screening for the SRY gene was carried out by fluorescence in-situ hybridization or by PCR. Results Cytogenetic results showed a prevalence of the 45,X karyotype in 46% of patients and various proportions of the other karyotypes. However, genotype–phenotype correlation revealed several discrepancies regarding the major signs and the age at diagnosis. The comparison of the approaches used for the screening of the SRY gene showed that karyotyping is unable to detect low 45,X/46,XY mosaicism and that it is the PCR that would be able to do, eliciting its role to make a reliable diagnosis. Conclusion The karyotype alone is not sufficient to make a TS diagnosis in cases of weak mosaicism, and the great heterogeneity that reigns the syndrome elicits an epigenetic and transcriptomic exploration of several genes that recently seem to be involved in the disease