Veselin Škrabić

Incidence of type 1 diabetes mellitus in 0 to 14‐yr‐old children in Croatia – 2004 to 2012 study

The incidence of type 1 diabetes mellitus (T1DM) among children and adolescents increased during the last 50 yr. The T1DM incidence in Croatia was 8.87/100.000/yr over 1995–2003, with an annual increase of 9%, which placed Croatia among countries with moderate risk for T1DM.

Clinical characteristics at presentation of type 1 diabetes mellitus in children younger than 15 years in Croatia

Abstract The aim of the study was to determine the clinical and biochemical characteristics of type 1 diabetes mellitus (DM) at presentation in children younger than 15 years in Croatia during a 9-year period, with special attention to diabetic ketoacidosis (DKA) incidence. The registered data set comprised blood glucose, pH, serum bicarbonate levels, and clinical symptoms at disease manifestation. During the study period, 692 children were diagnosed with type 1 DM. Polydipsia (96.7%), polyuria (96.05%), and weight loss (82.7%) were the most frequent symptoms anticipating disease detection. Enuresis was recorded in 11.55%. A total of 36.41% patients had DKA (pH<7.3) at disease onset. During the 9-year period, the percentage of children presenting with DKA at time of diagnosis decreased from 41.67% to 33.33% (z=1.68, p=0.046). A positive family history of DM, the only factor with an impact on the DKA incidence rate in our population, lowers the probability of the development of ketoacidosis. This study confirms the importance of the detection of the classic symptoms of polyuria, polydipsia, and weight loss in patients with new-onset type 1 DM. The percentage of patients with DKA at diabetes onset decreased during the observed period but is still high and includes one-third of all patients. This is why in every acutely ill child, especially at a younger age, one should evaluate the possibility of type 1 DM to avoid the development of ketoacidosis.

Classical Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency in Croatia between 1995 and 2006

Aims: To evaluate the incidence, gender, symptoms and age at diagnosis among patients with classical congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency in Croatia. Methods: Data were collected retrospectively for all classical CAH patients born or electively aborted following prenatal diagnosis between 01.01.1995 and 31.12.2006 and were compared with the data of the previously conducted study evaluating CAH patients discovered between 1964 and 1984. Results: During a 12-year period, 34 classical CAH patients were born. There were 20 salt-wasting (SW) (12 females/8 males) and 14 simple virilizing (SV) patients (7 females/7 males). If 3 female fetuses, electively aborted, were added, that would be a total of 37 CAH patients. With 532,942 live births and 34 CAH patients born over this period, incidence of classical CAH was estimated to 1:15,574 or 1:14,403 if 3 electively aborted fetuses were included. The lower incidence of SW boys compared to SW girls (8:12) and similar number of SW and SV boys (8:7) indicate that substantial proportion of SW boys die unrecognized. Owing to better health care, diagnosis was established significantly earlier in SW and SV girls compared to the period of 1964–1984 (p < 0.003). During 1995–2006, none of the patients died following the diagnosis of CAH, and there was no erroneous sex assignment. Conclusion: Despite of improvement in health care, diagnosis of CAH in Croatia is still delayed and some of the patients go unrecognized or die. Therefore, we think that the results of our study support the need for the introduction of newborn screening.

Molecular genetic analysis in 93 patients and 193 family members with classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Croatia.

Congenital adrenal hyperplasia owing to 21-hydroxylase deficiency is caused by mutation in the CYP21A2 gene. The frequency and spectrum of CYP21A2 mutations and genotype-phenotype correlations among different populations are variable. Aim of this study was to define mutation frequency and spectrum of CYP21A2 gene mutations in patients with classical 21-hydroxylase deficiency (21OHD) and their family members in Croatia and study genotype-phenotype correlation. Clinical features and mutations of CYP21A2 gene in 93 unrelated 21OHD patients and 193 family members were examined. In this cohort, 66 patients were affected with salt wasting (SW) form, and 27 were affected with simple virilizing (SV) form of the disease. Mutations were identified in both alleles (67% compound heterozygous and 33% homozygous) in 91 of 93 patients. Deletions and conversions were found in 18.8% and point mutations in 79.6% alleles. Mutations in 3 alleles (1.6%) remained unidentified (in one patient we found only one, while in other no mutations were found at all). The most common point mutations were Intron 2 splice mutation IVS2-13 A/C>G (35.5%) and p.R357W (16.7%). Genotypes were categorized into Groups 0, A, B and C according to the extent of enzyme impairment. Genotype-phenotype concordance was 100%, 85% and 75% for Groups 0, A and B, respectively. Since only classical 21OHD patients were studied, Group C comprised solely p.P31L mutation and had 73% patients with SV and 27% with SW phenotype. Intrafamilial phenotypic variability was found in two families. CYP21A2 genetic analysis in 193 family members showed that 126 parents were heterozygous carriers, 3 were newly discovered patients, 2 fathers were not biological parents, and mutations were not detected in 3. Among 59 siblings, 32 were heterozygous carriers, 15 carried normal alleles, and 12 were patients (4 newly diagnosed). Genotype-phenotype divergence observed in this study suggests caution in preconceptional counseling and prenatal diagnosis of CAH. High frequency of p.R357W mutation was found in Croatian patients with classical 21-OHD. Genotyping of family members discovered new patients and thus avoided pitfalls in genetic counseling when the parents were found to be affected.

Nonclassic 21-hydroxylase deficiency in Croatia.

This is the first report of nonclassic congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency in Croatia in which the patients have been evaluated clinically, hormonally, and by molecular genetic analysis. Genetic analysis was performed on 18 Croatian patients with nonclassic CAH due to 21-OH deficiency using allele-specific PCR. ACTH stimulation testing and HLA typing were used to evaluate patients hormonally. Molecular genetic analysis revealed a variety of mutations in individuals with different clinical symptoms, including precocious pubarche, hirsutism, (dysmenorrhea, subfertility and clitoromegaly. Serum stimulated 17-hydroxyprogesterone (17-OHP) levels indicated that all patients fell within the acceptable range for nonclassic congenital adrenal hyperplasia. Clinical and genetic analysis confirmed nonclassic 21-OH deficiency in our Croatian sample of ten males and eight females. This study shows that genotype does not necessarily predict fertility status in our group of affected patients.

Five patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (one with associated neuroblastoma) discovered in three generations of one family.

Background: Most patients with 21-hydroxylase deficiency (21-OHD) are compound heterozygous carriers. Their phenotype usually reflects a less severe allelic mutation, although discordance between the genotype and the phenotype has been observed. Case Report: We present 5 patients with congenital adrenal hyperplasia (CAH) due to 21-OHD belonging to the 3 generations of the same family (grandmother, parents and their 2 children). As each patient carries at least one mild mutation of the CYP21 gene, their genotypes correspond to nonclassical CAH. The propositus is the older brother, who is compound heterozygous with a mild and severe CYP21 mutation (P30L/R356W). In spite of one mild CYP21 mutation, he presented with the clinical picture of a simple virilizing form of 21-OHD and required glucocorticoid replacement therapy from the age of 4. Both probands’ parents are compound heterozygous carriers of different CYP21 gene mutations causing various degrees of enzymatic activity impairment, which explains the different genotypes and phenotypes in their offspring. The probands’ mother, besides the nonclassical 21-OHD, also had neuroblastoma of the adrenal gland. Conclusion: The potential discordance between the genotype and the phenotype in some patients with CAH is emphasized. The existence of a mild CYP21 mutation P30L in a compound heterozygous with CAH might be associated with progressive virilization requiring glucocorticoid therapy from early childhood. The occurrence of neuroblastoma with 21-OHD may support the hypothesis that an impairment in the synthesis and secretion of glucocorticoids may play role in the development and functioning of the adrenal medulla.

IL12RB2 gene is associated with the age of type 1 diabetes onset in Croatian family Trios.

Background Common complex diseases are influenced by both genetic and environmental factors. Many genetic factors overlap between various autoimmune diseases. The aim of the present study is to determine whether four genetic variants known to be risk variants for several autoimmune diseases could be associated with an increased susceptibility to type 1 diabetes mellitus. Methods and Findings We genotyped four genetic variants (rs2358817, rs1049550, rs6679356, rs9865818) within VTCN1, ANXA11, IL12RB2 and LPP genes respectively, in 265 T1DM family trios in Croatian population. We did not detect association of these polymorphisms with T1DM. However, quantitative transmission disequilibrium test (QTDT, orthogonal model) revealed a significant association between the age of onset of T1DM and IL12RB2 rs6679356 variant. An earlier onset of T1DM was associated with the rs6679356 minor dominant allele C (p = 0.005). The association remained significant even after the Bonferroni correction for multiple testing and permutation. Conclusions Variants originally associated with juvenile idiopathic arthritis (VTCN1 gene), sarcoidosis (ANXA11 gene), primary biliary cirrhosis (IL12RB2 gene) and celiac disease (LPP gene) were not associated with type 1 diabetes in our dataset. Nevertheless, association of IL12RB2 rs6679356 polymorphism with the age of T1DM onset suggests that this gene plays a role in defining the time of disease onset.

Acute bilateral cataract with phacomorphic glaucoma in a girl with newly diagnosed type 1 diabetes mellitus.

The authors present a rare case of acute bilateral cataract with phacomorphic glaucoma in a girl with newly diagnosed type 1 diabetes mellitus without a known history of ocular problems. Within 3 months after the diagnosis of diabetes mellitus, she presented with high intraocular pressure. Her visual acuity was limited to hand motions. The patient required immediate surgical intervention. Postoperatively, the intraocular pressure normalized and bilateral visual acuity was 6/6.

Cataract as Early Ocular Complication in Children and Adolescents with Type 1 Diabetes Mellitus

Cataract is a rare manifestation of ocular complication at an early phase of T1DM in the pediatric population. The pathophysiological mechanism of early diabetic cataract has not been fully understood; however, there are many theories about the possible etiology including osmotic damage, polyol pathway, and oxidative stress. The prevalence of early diabetic cataract in the population varies between 0.7 and 3.4% of children and adolescents with T1DM. The occurrence of diabetic cataract in most pediatric patients is the first sign of T1DM or occurs within 6 months of diagnosis of T1DM. Today, there are many experimental therapies for the treatment of diabetic cataract, but cataract surgery continues to be a gold standard in the treatment of diabetic cataract. Since the cataract is the leading cause of visual impairment in patients with T1DM, diabetic cataract requires an initial screening as well as continuous surveillance as a measure of prevention and this should be included in the guidelines of pediatric diabetes societies.

Glycosyltransferase B4GALNT1 and type 1 diabetes in Croatian population: clinical investigation.

OBJECTIVES Type 1 diabetes mellitus (T1DM) is an autoimmune disease characterized by destruction of pancreatic beta cells. Gangliosides are thought to be a target of a variety of anti-islet autoantibodies. The formation of gangliosides is catalyzed by addition of sugar residues to complex glycoconjugate molecules by glycosyltransferases. Beta-1,4-N-acetyl-galactosaminyl transferase 1 is the enzyme involved in the synthesis of asialo, a, b and c-series gangliosides and it is coded by B4GALNT1 gene. DESIGN AND METHODS We genotyped 2 B4GALNT1 tagSNPs, designed to capture 100% of common variation in the region, in 202 families and 199 controls from the Croatian population. RESULTS Transmission disequilibrium test and case-control analysis did not detect an association of B4GALNT1 gene with T1DM. CONCLUSIONS Expression of gangliosides requires coordinated work of many genes. There is enough evidence showing that gangliosides are plausible contributors to T1DM pathological processes and, therefore, future studies on different glycosyltransferase genes are necessary.