Timing of Puberty, Pubertal Growth, and Adult Height in Short Children Born Small for Gestational Age Treated With Growth Hormone

CONTEXT

Growth hormone (GH) is used to treat short children born small for gestational age (SGA); however, the effects of treatment on pubertal timing and adult height are rarely studied.

OBJECTIVE

To evaluate adult height and peak height velocity in short GH-treated SGA children.

METHODS

Prospective longitudinal multicenter study. Participants were short children born SGA treated with GH therapy (n = 102). Adult height was reported in 47 children. A reference cohort of Danish children was used. Main outcome measures were adult height, peak height velocity, age at peak height, and pubertal onset. Pubertal onset was converted to SD score (SDS) using Danish reference data.

RESULTS

Gain in height SDS from start of treatment until adult height was significant in both girls (0.94 [0.75; 1.53] SDS, P = .02) and boys (1.57 [1.13; 2.15] SDS, P < .001). No difference in adult height between GH dosage groups was observed. Peak height velocity was lower than a reference cohort for girls (6.5 [5.9; 7.6] cm/year vs 7.9 [7.4; 8.5] cm/year, P < .001) and boys (9.5 [8.4; 10.7] cm/year vs 10.1 [9.7; 10.7] cm/year, P = .002), but no difference in age at peak height velocity was seen. Puberty onset was earlier in SGA boys than a reference cohort (1.06 [-0.03; 1.96] SDS vs 0 SDS, P = .002) but not in girls (0.38 [-0.19; 1.05] SDS vs 0 SDS, P = .18).

CONCLUSION

GH treatment improved adult height. Peak height velocity was reduced, but age at peak height velocity did not differ compared with the reference cohort. SGA boys had an earlier pubertal onset compared with the reference cohort.

Increases in Bioactive IGF do not Parallel Increases in Total IGF-I During Growth Hormone Treatment of Children Born SGA

BACKGROUND

Some children born small for gestational age (SGA) experience supra-physiological insulin-like growth factor-I (IGF-I) concentrations during GH treatment. However, measurements of total IGF-I concentrations may not reflect the bioactive fraction of IGF-I which reaches the IGF-I receptor at target organs. We examined endogenous IGF-bioactivity using an IGF-I kinase receptor activation (KIRA) assay that measures the ability of IGF-I to activate the IGF-IR in vitro.

AIM

To compare responses of bioactive IGF and total IGF-I concentrations in short GH treated SGA children in the North European Small for Gestational Age Study (NESGAS).

MATERIAL AND METHOD

In NESGAS, short SGA children (n = 101, 61 males) received GH at 67 µg/kg/day for 1 year. IGF-I concentrations were measured by Immulite immunoassay and bioactive IGF by in-house KIRA assay.

RESULTS

Bioactive IGF increased with age in healthy pre-pubertal children (n = 94). SGA children had low-normal bioactive IGF levels at baseline (-0.12 (1.8 SD), increasing significantly after one year of high-dose GH treatment to 1.1 (1.4) SD, P < 0.01. Following high-dose GH, 68% (n = 65) of SGA children had a total IGF-I concentration >2SD (mean IGF-I 2.8 SDS), whereas only 15% (n = 15) had levels of bioactive IGF slightly above normal reference values. At baseline, bioactive IGF (SDS) was significantly correlated to height (SDS) (r = 0.29, P = 0.005), in contrast to IGF-I (SDS) (r = 0.17, P = 0.10). IGF-I (SDS) was inversely correlated to delta height (SDS) after one year of high-dose GH treatment (r = -0.22, P = 0.02).

CONCLUSION

In contrast to total IGF-I concentrations, bioactive IGF stayed within the normal reference ranges for most SGA children during the first year of GH treatment.

Reduced display of conformational epitopes in the N-terminal truncated GAD65 isoform: relevance for people with stiff person syndrome or DQ8/8-positive Type 1 diabetes mellitus

AIMS

To investigate whether the N-terminal truncated glutamic acid decarboxylase 65 (GAD65) isoform is as well recognized by people with stiff person syndrome as it is by people with Type 1 diabetes, and whether conformational GAD65 antibody epitopes are displayed properly by the isoform.

METHODS

GAD65 antibody-positive healthy individuals (n=13), people with stiff-person syndrome (n=15) and children with new-onset Type 1 diabetes (n=654) were analysed to determine binding to full-length GAD65 and the N-terminal truncated GAD65 isoform in each of these settings. GAD65 autoantibody epitope specificity was correlated with binding ratios of full-length GAD65/N-terminal truncated GAD65.

RESULTS

The N-terminal truncated GAD65 isoform was significantly less recognized in GAD65Ab-positive people with stiff-person syndrome (P=0.002) and in healthy individuals (P=0.0001) than in people with Type 1 diabetes. Moreover, at least two specific conformational GAD65Ab epitopes were not, or were only partially, presented by the N-terminal truncated GAD65 isoform compared to full-length GAD65. Finally, an N-terminal conformational GAD65Ab epitope was significantly less recognized in DQ8/8 positive individuals with Type 1 diabetes (P=0.02).

CONCLUSIONS

In people with stiff person syndrome preferred binding to the full-length GAD65 isoform over the N-terminal truncated molecule was observed. This binding characteristic is probably attributable to reduced presentation of two conformational epitopes by the N-terminal truncated molecule. These findings support the notion of disease-specific GAD65Ab epitope specificities and emphasize the need to evaluate the applicability of novel assays for different medical conditions.

The Better Diabetes Diagnosis (BDD) study - A review of a nationwide prospective cohort study in Sweden

The incidence of type 1 diabetes (T1D) in Sweden is one of the highest in the world. However, the possibility of other types of diabetes must also be considered. In addition, individuals with T1D constitute a heterogeneous group. A precise classification of diabetes is a prerequisite for optimal outcome. For precise classification, knowledge on the distribution of genetic factors, biochemical markers and clinical features in individuals with new onset of diabetes is needed. The Better Diabetes Diagnosis (BDD), is a nationwide study in Sweden with the primary aim to facilitate a more precise classification and diagnosis of diabetes in order to enable the most adequate treatment for each patient. Secondary aims include identification of risk factors for diabetes-related co-morbidities. Since 2005, data on almost all children and adolescents with newly diagnosed diabetes in Sweden are prospectively collected and including heredity of diabetes, clinical symptoms, levels of C peptide, genetic analyses and detection of autoantibodies. Since 2011, analyses of HLA profile, autoantibodies and C peptide levels are part of clinical routine in Sweden for all pediatric patients with suspected diagnosis of diabetes. In this review, we present the methods and main results of the BDD study so far and discuss future aspects.

The exon3-deleted growth hormone receptor gene polymorphism (d3-GHR) is associated with insulin and spontaneous growth in short SGA children (NESGAS)

OBJECTIVE

The effect of a common polymorphism in the Growth Hormone (GH) receptor (d3-GHR) gene on growth, metabolism and body composition was examined in short children born small for gestational age (SGA) on GH treatment.

DESIGN

In 96 prepubertal, short SGA children treated with high-dose GH (67μg/kg/day) in the NESGAS study, insulin sensitivity (IS), insulin secretion and disposition index (DI) were determined during the first year of treatment. Body composition was analysed by DXA. The d3-GHR locus was determined by simple multiplex PCR.

RESULTS

At baseline, children in the d3-GHR group (d3/fl (n=37), d3/d3 (n=7)) had significantly lower IS (median (25-75 percentile)) (223.3% (154.4-304.8)) vs. (269.7% (185.1-356.7)) (p=0.03) and higher concentrations of glucose (mean (SD)) (4.4mmol/L (0.6) vs. 4.2mmol/L (0.7)) (p=0.03), C-peptide (232.1pmol/L (168.8-304.1) vs. 185.1pmol/L (137.7-253.9)) (p=0.04) and insulin (19.2pmol/L (11.8-32.2)) vs. (13.7pmol/L (9.3-20.8)) (p=0.04) compared to children homozygous for the full length allele (fl/fl-GHR (n=52)). There were no differences in DI or insulin secretion. Postnatal, spontaneous growth was significantly greater in the d3-GHR group compared to the fl/fl-GHR group (p=0.02). There were no significant differences in growth response, body composition or metabolism after one year of GH therapy.

CONCLUSION

Short SGA children carrying the d3-GHR polymorphism had increased spontaneous growth, lower IS and a compensatory increase in glucose, C-peptide and insulin before GH therapy compared to children homozygous for the full-length allele.

Growth hormone dose-dependent pubertal growth: a randomized trial in short children with low growth hormone secretion

BACKGROUND/AIMS

Growth hormone (GH) treatment regimens do not account for the pubertal increase in endogenous GH secretion. This study assessed whether increasing the GH dose and/or frequency of administration improves pubertal height gain and adult height (AH) in children with low GH secretion during stimulation tests, i.e. idiopathic isolated GH deficiency.

METHODS

A multicenter, randomized, clinical trial (No. 88-177) followed 111 children (96 boys) at study start from onset of puberty to AH who had received GH 33 µg/kg/day for ≥1 year. They were randomized to receive 67 µg/kg/day (GH(67)) given as one (GH(67×1); n = 35) or two daily injections (GH(33×2); n = 36), or to remain on a single 33 µg/kg/day dose (GH(33×1); n = 40). Growth was assessed as heightSDSgain for prepubertal, pubertal and total periods, as well as AHSDS versus the population and the midparental height.

RESULTS

Pubertal heightSDSgain was greater for patients receiving a high dose (GH(67), 0.73) than a low dose (GH(33×1), 0.41, p < 0.05). AHSDS was greater on GH(67) (GH(67×1), -0.84; GH(33×2), -0.83) than GH(33) (-1.25, p < 0.05), and heightSDSgain was greater on GH(67) than GH(33) (2.04 and 1.56, respectively; p < 0.01). All groups reached their target heightSDS.

CONCLUSION

Pubertal heightSDSgain and AHSDS were dose dependent, with greater growth being observed for the GH(67) than the GH(33) randomization group; however, there were no differences between the once- and twice-daily GH(67) regimens. © 2014 S. Karger AG, Basel.

Genetic markers of insulin sensitivity and insulin secretion are associated with spontaneous postnatal growth and response to growth hormone treatment in short SGA children: the North European SGA Study (NESGAS)

PURPOSE

The wide heterogeneity in the early growth and metabolism of children born small for gestational age (SGA), both before and during GH therapy, may reflect common genetic variations related to insulin secretion or sensitivity.

METHOD

Combined multiallele single nucleotide polymorphism scores with known associations with insulin sensitivity or insulin secretion were analyzed for their relationships with spontaneous postnatal growth and first-year responses to GH therapy in 96 short SGA children.

RESULTS

The insulin sensitivity allele score (GS-InSens) was positively associated with spontaneous postnatal weight gain (regression coefficient [B]: 0.12 SD scores per allele; 95% confidence interval [CI], 0.01-0.23; P = .03) and also in response to GH therapy with first-year height velocity (B: 0.18 cm/y per allele; 95% CI, 0.02-0.35; P = .03) and change in IGF-1 (B: 0.17 SD scores per allele; 95% CI, 0.00-0.32; P = .03). The association with first-year height velocity was independent of reported predictors of response to GH therapy (adjusted P = .04). The insulin secretion allele score (GS-InSec) was positively associated with spontaneous postnatal height gain (B: 0.15; 95% CI, 0.01-0.30; P = .03) and disposition index both before (B: 0.02; 95% CI, 0.00-0.04; P = .04) and after 1 year of GH therapy (B: 0.03; 95% CI, 0.01-0.05; P = .002), but not with growth and IGF-1 responses to GH therapy. Neither of the allele scores was associated with size at birth.

CONCLUSION

Genetic allele scores indicative of insulin sensitivity and insulin secretion were associated with spontaneous postnatal growth and responses to GH therapy in short SGA children. Further pharmacogenetic studies may support the rationale for adjuvant therapies by informing the mechanisms of treatment response.

A randomised controlled trial evaluating IGF1 titration in contrast to current GH dosing strategies in children born small for gestational age: the North European Small-for-Gestational-Age Study

BACKGROUND

Short children born small for gestational age (SGA) are treated with a GH dose based on body size, but treatment may lead to high levels of IGF1. The objective was to evaluate IGF1 titration of GH dose in contrast to current dosing strategies.

METHODS

In the North European Small-for-Gestational-Age Study (NESGAS), 92 short pre-pubertal children born SGA were randomised after 1 year of high-dose GH treatment (67 μg/kg per day) to three different regimens: high dose (67 μg/kg per day), low dose (35 μg/kg per day) or IGF1 titration.

RESULTS

The average dose during the second year of the randomised trial did not differ between the IGF1 titration group (38 μg/kg per day, s.d. 0.019) and the low-dose group (35 μg/kg per day, s.d. 0.002; P=0.46), but there was a wide variation in the IGF1 titration group (range 10-80 μg/kg per day). The IGF1 titration group had significantly lower height gain (0.17 SDS, s.d. 0.18) during the second year of the randomised trial compared with the high-dose group (0.46 SDS, s.d. 0.25), but not significantly lower than the low-dose group (0.23 SDS, s.d. 0.15; P=0.17). The IGF1 titration group had lower IGF1 levels after 2 years of the trial (mean 1.16, s.d. 1.24) compared with both the low-dose (mean 1.76, s.d. 1.48) and the high-dose (mean 2.97, s.d. 1.63) groups.

CONCLUSION

IGF1 titration of GH dose in SGA children proved less effective than current dosing strategies. IGF1 titration resulted in physiological IGF1 levels with a wide range of GH dose and a poorer growth response, which indicates the role of IGF1 resistance and highlights the heterogeneity of short SGA children.

Antibodies to influenza virus A/H1N1 hemagglutinin in Type 1 diabetes children diagnosed before, during and after the SWEDISH A(H1N1)pdm09 vaccination campaign 2009-2010

We determined A/H1N1-hemagglutinin (HA) antibodies in relation to HLA-DQ genotypes and islet autoantibodies at clinical diagnosis in 1141 incident 0.7-to 18-year-old type 1 diabetes patients diagnosed April 2009-December 2010. Antibodies to (35) S-methionine-labelled A/H1N1 hemagglutinin were determined in a radiobinding assay in patients diagnosed before (n = 325), during (n = 355) and after (n = 461) the October 2009-March 2010 Swedish A(H1N1)pdm09 vaccination campaign, along with HLA-DQ genotypes and autoantibodies against GAD, insulin, IA-2 and ZnT8 transporter. Before vaccination, 0.6% patients had A/H1N1-HA antibodies compared with 40% during and 27% after vaccination (P < 0.0001). In children <3 years of age, A/H1N1-HA antibodies were found only during vaccination. The frequency of A/H1N1-HA antibodies during vaccination decreased after vaccination among the 3 < 6 (P = 0.006) and 13 < 18 (P = 0.001), but not among the 6 < 13-year-olds. HLA-DQ2/8 positive children <3 years decreased from 54% (15/28) before and 68% (19/28) during, to 30% (9/30) after vaccination (P = 0.014). Regardless of age, DQ2/2; 2/X (n = 177) patients had lower frequency (P = 0.020) and levels (P = 0.042) of A/H1N1-HA antibodies compared with non-DQ2/2; 2/X (n = 964) patients. GADA frequency was 50% before, 60% during and 51% after vaccination (P = 0.009). ZnT8QA frequency increased from 30% before to 34% during and 41% after vaccination (P = 0.002). Our findings suggest that young (<3 years) along with DQ2/2; 2/X patients were low responders to Pandemrix(®) . As the proportion of DQ2/8 patients <3 years of age decreased after vaccination and the frequencies of GADA and ZnT8QA were enhanced, it cannot be excluded that the vaccine affected clinical onset of type 1 diabetes.

Baseline IGF-I levels determine insulin secretion and insulin sensitivity during the first year on growth hormone therapy in children born small for gestational age. Results from a North European Multicentre Study (NESGAS)

OBJECTIVE

Developmental programming alters growth and metabolic outcome in children born small for gestational age (SGA). We explored insulin and glucose metabolism in SGA children treated with a fixed GH dose over 1 year.

METHODS

In the North European Small for Gestational Age Study (NESGAS), 110 short SGA children received GH at 67 µg/kg/day for 1 year. Insulin secretion was assessed by acute insulin response (AIR), insulin sensitivity (IS) by HOMA and disposition index (DI) by insulin secretion adjusted for IS.

RESULTS

First-year GH therapy led to increases in height and IGF-I standard deviation score (SDS), and reductions in IS (p < 0.0001). Compensatory increases in AIR (p < 0.0001) were insufficient and resulted in reduced DI (p = 0.032). Children in the highest IGF-I SDS tertile at baseline were the least insulin sensitive at baseline (p = 0.024) and 1 year (p = 0.006). IGF-I responses after 1 year were positively related to AIR (r = 0.30, p = 0.007) and DI (r = 0.29, p = 0.005).

CONCLUSION

In SGA children treated with a high GH dose for 1 year, baseline IGF-I levels were related to IS whilst gains in height and IGF-I responses were associated with insulin secretion. Defining heterogeneity in IGF-I in SGA children may be useful in predicting growth and metabolic response.

Decline of C-peptide during the first year after diagnosis of Type 1 diabetes in children and adolescents

AIMS/HYPOTHESIS

We studied the decline of C-peptide during the first year after diagnosis of Type 1 diabetes (T1D), and its relation to various factors.

METHODS

3824/4017 newly diagnosed patients (95%) were classified as T1D in a national study. In a non-selected subgroup of 1669 T1D patients we determined non-fasting C-peptide both at diagnosis and after 1 year, and analyzed decline in relation to clinical symptoms and signs, initial C-peptide and occurrence of auto-antibodies.

RESULTS

Younger children lost more C-peptide (p<0.001) and the higher the C-peptide at diagnosis the larger the decline during the first year (p<0.0000). Patients with higher BMI had higher C-peptide at diagnosis but lost more (p<0.01), and those with lower HbA1c, without symptoms and signs at diagnosis, and with higher BMI, had higher C-peptide at diagnosis, but lost more during the first year (p<0.001). Finally, patients diagnosed during autumn had higher C-peptide at diagnosis, but lost more during the coming year (p<0.001). Occurrence of auto-antibodies did not correlate with C-peptide decline, except possibly for a more rapid loss in IAA-positive patients.

CONCLUSIONS/INTERPRETATION

Even in a restricted geographical area and narrow age range (<18 years), the natural course of Type 1 diabetes is heterogeneous. This should be considered in clinical trials.

Gestational diabetes mellitus is associated with TCF7L2 gene polymorphisms independent of HLA-DQB1*0602 genotypes and islet cell autoantibodies

AIMS

To test whether the TCF7L2 gene was associated with gestational diabetes, whether the association between TCF7L2 and gestational diabetes was independent of HLA-DQB1*0602 and islet cell autoantibodies, as well as maternal age, number of pregnancies, family history of diabetes and the HLA-DQB1 genotypes, and to test whether the distribution of HLA-DQB1 alleles was affected by country of birth.

METHODS

We genotyped the rs7903146, rs12255372 and rs7901695 single nucleotide polymorphisms of the TCF7L2 gene in 826 mothers with gestational diabetes and in 1185 healthy control subjects in the Diabetes Prediction in Skåne Study. The mothers were also typed for HLA-DQB1 genotypes and tested for islet cell autoantibodies against GAD65, insulinoma-associated antigen-2 and insulin.

RESULTS

The heterozygous genotypes CT, GT and TC of the rs7903146 (T is risk for Type 2 diabetes), rs12255372 (T is risk for Type 2 diabetes) and rs7901695 (C is risk for Type 2 diabetes), respectively, as well as the homozygous genotypes TT, TT and CC of the rs7903146, rs12255372 and rs7901695, respectively, were strongly associated with gestational diabetes (P < 0.0001). These associations remained statistically significant after adjusting for maternal age, number of pregnancies, family history of diabetes and HLA-DQ genotypes and were independent of the presence of islet cell autoantibodies. No interaction was observed between TCF7L2 and HLA-DQB1*0602, which was shown to be negatively associated with gestational diabetes in mothers born in Sweden (P = 0.010).

CONCLUSIONS

The TCF7L2 was associated with susceptibility for gestational diabetes independently of the presence of HLA-DQB1*0602 and islet cell autoantibodies and other factors such as maternal age, number of pregnancies, family history of diabetes and other HLA-DQ genotypes. The HLA-DQB1*0602 was negatively associated with gestational diabetes in mothers born in Sweden.

Type 1 diabetes patients born to immigrants to Sweden increase their native diabetes risk and differ from Swedish patients in HLA types and islet autoantibodies

AIM

To determine whether type 1 diabetes mellitus (T1DM) patients, having parents who immigrated to Sweden, have increased T1DM risk before 18 yr compared with countries of origin. We also determined whether they have different human leukocyte antigen (HLA) genetic markers and islet autoantibodies at diagnosis compared with Swedish patients.

METHODS

A total of 1988 (53% males) newly diagnosed and confirmed T1DM patients <18 yr registered within the Better Diabetes Diagnosis (BDD) study (May 2005 to September 2008) were included. Participants were classified into three groups: Swedish, non-Swedish, and Mixed-origin patients according to country of origin of two generations (parents and grandparents). These groups were compared with respect to T1DM HLA markers and islet autoantibodies [glutamic acid decarboxylase autoantibodies (GAD65Ab), insulin autoantibodies (IAA), and islet antigen-2 autoantibodies (IA-2Ab)].

RESULTS

Only 30 (1.5%) patients were born outside Sweden. Swedish patients constituted 66%, non-Swedish patients 8%, Mixed origins 17%, and 9% were of uncertain origin. Confirmed T1DM in patients within the study was 22 (95% CI: 21-23) patients/10(5)/yr rate for Swedish patients compared with 14 (95% CI: 13-15) among non-Swedish patients. The HLA-DQ8 haplotype (p < 0.0001) and DQ2/8 genotype (p < 0.02) predominated among Swedish compared with non-Swedish patients. In contrast, DQ2 was the most frequent haplotype among non-Swedish patients [OR = 1.5 (95% CI: 1.0-2.0), p < 0.04]. Multiple (≥2) autoantibodies (p < 0.04) and specifically IA-2Ab (p < 0.001) were most prevalent among the Swedish patients. Multiple autoantibodies were associated with DQ8 among the Swedish patients only (p < 0.001).

CONCLUSION

Patients born to parents who had immigrated to the high T1DM incidence environment of Sweden have, compared with Swedish patients, more frequent HLA-DQ2 genetic markers and are diagnosed more often with GAD65Ab.

Comparison of radioimmunoprecipitation with luciferase immunoprecipitation for autoantibodies to GAD65 and IA-2beta

OBJECTIVE

To compare the sensitivity and specificity of luciferase immunoprecipitation (LIPS) with radioimmunoprecipitation (RIP) for the measurement of autoantibodies to the type 1 diabetes autoantigens glutamic acid decarboxylase 65 (GAD65) and insulinoma-associated protein (IA)-2beta.

RESEARCH DESIGN AND METHODS

Sera from 49 type 1 diabetic patients and 100 nondiabetic control subjects from Diabetes Antibody Standardization Program 2007 were used to screen for autoantibodies to GAD65. An additional 200 type 1 diabetic patients and 200 nondiabetic control subjects were used to validate the GAD65 results and screen for autoantibodies to IA-2beta.

RESULTS

LIPS showed equal sensitivity and specificity to RIP for detecting autoantibodies to GAD65 and IA-2beta. Receiver-operating characteristic analysis revealed that the detection of autoantibodies to GAD65 and IA-2beta by LIPS and RIP were not statistically different.

CONCLUSIONS

The LIPS assay does not require the use of radioisotopes or in vitro transcription/translation and is a practical alternative at the clinical level for the RIP assay.

Reticulocytes and insulin binding to erythrocytes

The relationship between erythrocyte insulin receptors and the reticulocytes were studied in a group with a varying degree of reticulocytosis. The maximal I-insulin binding to erythrocytes varied between 6% and 37% and it showed a highly significant positive correlation with the reticulocyte count (r=0.85). The highest binding was found in a patient with hereditary spherocytosis and very active hematopoiesis (312 x 10(9) reticulocytes per litre). The results suggest that insulin receptors are predominantly localized to the young erythrocytes, and that further studies are needed to characterize the dependence of the receptor on erythrocyte maturation.

Temporal trends of HLA genotype frequencies of type 1 diabetes patients in Sweden from 1986 to 2005 suggest altered risk

The aim of this study was to compare the frequency of human leukocyte antigen (HLA) genotypes in 1-18-year-old patients with type 1 diabetes newly diagnosed in 1986-1987 (n = 430), 1996-2000 (n = 342) and in 2003-2005 (n = 171). We tested the hypothesis that the HLA DQ genotype distribution changes over time. Swedish type 1 diabetes patients and controls were typed for HLA using polymerase chain reaction amplification and allele specific probes for DQ A1* and B1* alleles. The most common type 1 diabetes HLA DQA1*-B1*genotype 0501-0201/0301-0302 was 36% (153/430) in 1986-1987 and 37% (127/342) in 1996-2000, but decreased to 19% (33/171) in 2003-2005 (P \ 0.0001). The 0501-0201/0501-0201 genotype increased from 1% in 1986-1987 to 7% in 1996-2000 (P = 0.0047) and to 5% in 2003-2005 (P > 0.05). This study in 1-18-year-old Swedish type 1 diabetes patients supports the notion that there is a temporal change in HLA risk.

Selective screening of secretory vesicle-associated proteins for autoantigens in type 1 diabetes: VAMP2 and NPY are new minor autoantigens

The four major autoantigens (IA-2, IA-2 beta, GAD65 and insulin) of type 1 diabetes are all associated with dense core or synaptic vesicles. This raised the possibility that other secretory vesicle-associated proteins might be targets of the autoimmune response in type 1 diabetes. To test this hypothesis 56 proteins, two-thirds of which are associated with secretory vesicles, were prepared by in vitro transcription/translation and screened for autoantibodies by liquid phase radioimmunoprecipitation. Two secretory vesicle-associated proteins, VAMP2 and NPY, were identified as new minor autoantigens with 21% and 9%, respectively, of 200 type 1 diabetes sera reacting positively. These findings add support to the hypothesis that secretory vesicle-associated proteins are particularly important, but not the exclusive, targets of the autoimmune response in type 1 diabetes. Selective screening of the human proteome offers a useful approach for identifying new autoantigens in autoimmune diseases.

Two insulin gene single nucleotide polymorphisms associated with type 1 diabetes risk in the Finnish and Swedish populations

We have developed high-throughput tests for the detection of the insulin gene region SNPs -23HphI and -2221MspI. The potential of these markers to enhance the efficiency of type 1 diabetes risk screening was then evaluated by analyzing them in Finnish and Swedish populations. Blood spots on filter paper were analyzed using PCR followed by sequence-specific hybridization and time-resolved fluorometry reading. Distribution of the genotypes at both positions differed significantly among the affected children compared to the controls. The risk genotypes (CC, AA) were significantly more common in Finland than in Sweden, both among patients and controls. The VNTR genotype homozygous for the protective class III alleles showed a significantly stronger protective effect than the heterozygote (p=0.02). Analyzing both SNPs enabled the detection of VNTR class III subclasses IIIA and IIIB. The observed significance between effects of the protective genotypes was due to the strong protective effect of the IIIA/IIIA genotype. IIIA/IIIA was the only genotype with significant discrepancy between protective effects compared to the other class III genotypes. These observations suggest that heterogeneity between the protective IDDM2 lineages could exist, and analyzing both -23HphI and -2221MspI would thus potentially enhance the sensitivity and specificity of type 1 diabetes risk estimation.

IA-2 autoantibodies in incident type I diabetes patients are associated with a polyadenylation signal polymorphism in GIMAP5

In a large case-control study of Swedish incident type I diabetes patients and controls, 0-34 years of age, we tested the hypothesis that the GIMAP5 gene, a key genetic factor for lymphopenia in spontaneous BioBreeding rat diabetes, is associated with type I diabetes; with islet autoantibodies in incident type I diabetes patients or with age at clinical onset in incident type I diabetes patients. Initial scans of allelic association were followed by more detailed logistic regression modeling that adjusted for known type I diabetes risk factors and potential confounding variables. The single nucleotide polymorphism (SNP) rs6598, located in a polyadenylation signal of GIMAP5, was associated with the presence of significant levels of IA-2 autoantibodies in the type I diabetes patients. Patients with the minor allele A of rs6598 had an increased prevalence of IA-2 autoantibody levels compared to patients without the minor allele (OR=2.2; Bonferroni-corrected P=0.003), after adjusting for age at clinical onset (P=8.0 x 10(-13)) and the numbers of HLA-DQ A1*0501-B1*0201 haplotypes (P=2.4 x 10(-5)) and DQ A1*0301-B1*0302 haplotypes (P=0.002). GIMAP5 polymorphism was not associated with type I diabetes or with GAD65 or insulin autoantibodies, ICA, or age at clinical onset in patients. These data suggest that the GIMAP5 gene is associated with islet autoimmunity in type I diabetes and add to recent findings implicating the same SNP in another autoimmune disease.

SUMO4 M55V polymorphism affects susceptibility to type I diabetes in HLA DR3- and DR4-positive Swedish patients

SUMO4 M55V, located in IDDM5, has been a focus for debate because of its association to type I diabetes (TIDM) in Asians but not in Caucasians. The current study aims to test the significance of M55V association to TIDM in a large cohort of Swedish Caucasians, and to test whether M55V is associated in those carrying human leukocyte antigen (HLA) class II molecules. A total of 673 TIDM patients and 535 age- and sex-matched healthy controls were included in the study. PCR-RFLP was performed to identify the genotype and allele variations. Our data suggest that SUMO4 M55V is not associated with susceptibility to TIDM by itself. When we stratified our patients and controls based on heterozygosity for HLA-DR3/DR4 and SUMO4 genotypes, we found that presence of SUMO4 GG increased further the relative risk conferred by HLA-DR3/DR4 to TIDM, whereas SUMO4 AA decreased the risk. From the current study, we conclude that SUMO4 M55V is associated with TIDM in association with high-risk HLA-DR3 and DR4, but not by itself.

Levothyroxine treatment reduces thyroid size in children and adolescents with chronic autoimmune thyroiditis

CONTEXT

The use of levothyroxine to reduce thyroid size in pediatric patients with goiter due to chronic autoimmune thyroiditis (AIT) remains controversial. In overtly hypothyroid patients, reductions in thyroid volume have been reported, whereas the effect in subclinically hypothyroid and euthyroid patients is less clear.

OBJECTIVE

The objective of the study was to evaluate the effect of levothyroxine treatment on thyroid size (determined with thyroid ultrasonography) in children and adolescents with AIT.

DESIGN AND SETTING

This study included patients with AIT treated at a university hospital outpatient clinic between 1987 and 2004.

PATIENTS

Ninety children with AIT (73 girls and 17 boys, aged 6.1-17.7 yr) were included in the study.

INTERVENTION

Intervention was treatment with levothyroxine for a median 2.8 yr (range 0.5-10.2).

MAIN OUTCOME MEASURE

Change in thyroid volume sd score (SDS) during the study period was measured.

RESULTS

Median thyroid volume SDS was reduced in patients euthyroid (-0.4 SDS, P < 0.001), subclinically hypothyroid (-1.4 SDS, P < 0.001), and overtly hypothyroid (-1.8 SDS, P < 0.002) at diagnosis of AIT. Both hypothyroid and euthyroid patients with goiter (thyroid volume > 2.0 SDS) at baseline reduced their median thyroid volume SDS (-1.6 and -0.9, respectively, P < 0.001). Hypothyroid patients without goiter also reduced median thyroid volume SDS (-1.2, P < 0.004), whereas no change was noticed in euthyroid children without goiter.

CONCLUSIONS

Levothyroxine treatment is effective in reducing thyroid volume in pediatric patients and is suggested in treatment of goiter caused by AIT, especially in cases of hypothyroid, but also in euthyroid children.

Prevalence of celiac disease: before and after a national change in feeding recommendations

OBJECTIVE

A national change in infant feeding recommendations was proposed in 1996 in Sweden: a slow introduction to gluten during weaning was stressed, the recommendation being introduction at 4 instead of 6 months of age. The aim of the present study was to compare the prevalence of celiac disease in healthy young children born before and after the new feeding recommendations in 1996.

MATERIAL AND METHODS

Sera from 679 children at a median age of 2.9 years (range 2.5-4.2 years) born between January 1996 and November 1997 were investigated with IgA-antigliadin antibodies (AGA) and IgA-endomysial autoantibodies (EMA) and compared with 690 age-matched children born between July 1992 and June 1993. Children with a positive test for EMA and AGA or EMA only were re-tested, and if positive at follow up, investigated with intestinal biopsy.

RESULTS

At baseline, 2.2% (15/679) children were positive for EMA and another 0.6% (4/679) for both EMA and AGA. One child refused to be re-tested and eight children were still EMA positive at follow-up. Intestinal biopsy was performed in seven children (one declined biopsy), of whom three showed total villous atrophy. Two children with EMA titers 1:640, respectively, refused further participation in the study, but were strongly suspected to have celiac disease. In total, 0.7% (5/679) (95% confidence interval (CI) = 0.1-1.4%) were considered to have celiac disease compared with 1.3% (9/690) (95% CI = 0.4-2.2%) in the control group (p=0.4217). In addition, 0.3% of the children were diagnosed with symptomatic celiac disease compared with 0.7% in controls (p=0.0134).

CONCLUSIONS

The prevalence of symptomatic celiac disease declined after the infant dietary recommendations were introduced in 1996, but we could not find any difference in undiagnosed celiac disease between the screened children born before and those born after 1996.

Genetic and perinatal factors as risk for childhood type 1 diabetes

The mechanisms by which gestational infections, blood incompatibility, birth weight, mother's age and other prenatal or neonatal events increase the risk for type 1 diabetes are not understood. Studies so far have been retrospective, and there is a lack of population-based prospective studies. The possibility of identifying children at type 1 diabetes risk among first-degree relatives has resulted in prospective studies aimed at identifying postnatal events associated with the appearance of autoantibody markers for type 1 diabetes and a possible later onset of diabetes. However, the majority (85%) of new onset type 1 diabetes children do not have a first-degree relative with the disease. Population-based studies are therefore designed to prospectively analyse pregnant mothers and their offspring. One such study is DiPiS (Diabetes Prediction in Skåne), which is examining a total of about 10,000 pregnancies expected every year in the Skåne (Scania) region of Sweden that has 1.1 million inhabitants. Blood samples from all mothers in this region are obtained during pregnancy and at the time of delivery. Cord blood is analysed for HLA high-risk alleles and for autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GADA), the protein tyrosine phosphatase-related IA-2 antigen (IA-2A) and insulin (IAA) as a measure of prenatal autoimmune exposure. Identifying high-risk children by genetic, autoimmune and gestational risk factors followed by prospective analyses will make it possible to test the hypothesis that gestational events may trigger beta cell autoimmunity as a prerequisite for childhood type 1 diabetes.

Using radioligand-binding assays to measure tissue transglutaminase autoantibodies in young children

AIM

To measure autoantibodies against tissue transglutaminase (tTG) in young children prospectively screened for coeliac disease (CD).

METHODS

In total, 652 children aged 2.9 (2.5-4.2) y were analysed for IgA-tTG and IgG-tTG with radioligand-binding assays and IgA endomysial antibodies (EMA) by indirect immunofluorescence. Antibody-positive children were retested after 1.2 (range 0.2-1.9) y. Intestinal biopsy was performed on children with persistently high antibody levels.

RESULTS

In total, 3.2% (95% CI: 1.9-4.6%) of the 652 children were positive for at least one antibody at baseline: 2.5% (95% CI: 1.3-3.7%) for IgA-tTG, 1.7% (95% CI: 0.7-2.7%) for IgG-tTG and 2.9% (95% CI: 1.6-4.2%) for IgA-EMA, respectively. Ten children were positive for all three antibodies, five for both IgA-tTG and EMA, four for EMA only, one for IgA-tTG and another for IgG-tTG. IgA-EMA titres correlated with IgA-tTG levels (r = 0.73, p = 0.0003). At follow-up, seven of 20 children remained positive for all three antibodies, three for IgA-tTG only, one for both IgA-tTG and EMA, one for IgA-tTG and IgG-tTG, and the remaining child refused further participation. Three biopsies showed villous atrophy, two increased intraepithelial lymphocytes and two normal findings. Biopsy was not performed in four children with low or declining tTG antibody levels at follow-up and in one child who declined. CD was evident in 0.5% (95% CI: 0.0-1.0%) (3/652).

CONCLUSION

This study revealed a high number of young children positive for tTG antibodies as well as EMA, but the majority showed declining levels in both antibodies over time. We suggest using radioligand-binding assays for quantitative measurement of tTG antibodies when change in antibody levels is studied in young children.

Interpretation of normative thyroid volumes in children and adolescents: is there a need for a multivariate model?

The use of thyroid ultrasonography for determination of thyroid volume requires reliable reference criteria. The current World Health Organization/International Council for the Control of Iodine Deficiency Disorders (WHO/ICCIDD) reference has been questioned since iodine-sufficient children have been found throughout the world with distinctly smaller thyroid volumes. A difference in part explained by a systematic bias when generating the WHO/ICCIDD reference data. The objective with this study was to evaluate normative thyroid volumes in our region and, if possible, develop a multivariate model for their interpretation. Thyroid ultrasonography was performed and anthropometrical measurements were taken in 561 children and adolescents. The best predictor for thyroid volume in both girls and boys was body surface area (BSA), followed by age, weight, and height. References for normative thyroid volumes were calculated for each of the predictors. When these references were compared with other references throughout the world, the age-specific references were in good accord, but distinct differences were found between our BSA-specific references and other references based on a majority of children younger than ours. Using multivariate analyses, BSA and age were found to significantly influence thyroid volume, independently of each other. Multiple regression models by gender using BSA and age as predictors for thyroid volume were constructed. Using these models the difference between the BSA-specific references could be markedly reduced. To interpret thyroid volume accurately we propose the use of a multivariate model using age and BSA as predictors of thyroid volume.

Intrauterine exposure to maternal enterovirus infection as a risk factor for development of autoimmune thyroiditis during childhood and adolescence

Maternal intrauterine enterovirus infection during pregnancy increases the risk for the offspring to develop type 1 diabetes mellitus. Type 1 diabetes mellitus and autoimmune thyroiditits (AIT) are closely linked. A common pathogenetic factor is possible. The objective of this study was to investigate a possible association between maternal enterovirus infection during pregnancy and the development of AIT in the offspring. Sera taken at delivery from 31 mothers whose children subsequently developed AIT was analyzed for immunoglobulin (Ig)A, IgG, and IgM antibodies against enterovirus, and compared to a control group comprising 233 randomly selected maternal sera. Of the mothers whose children developed AIT, 5 of 31 (16%) were enterovirus IgM-positive, compared to 17 of 233 (7%) in the control group (p = 0.16). The age at diagnosis of AIT was significantly lower in the group of children with IgM-positive mothers compared to children with IgM-negative mothers (p < 0.05). In addition, 3 children (60%) in the IgM-positive group were overtly hypothyroid at diagnosis of AIT, compared to no child (0%) in the IgM-negative group (p < 0.01). No significant differences were found in IgA and IgG antibody titers between the mothers whose children developed AIT and the control group. Although this study did not have enough power to reveal intrauterine exposure to maternal enterovirus infection during pregnancy as a risk factor for development of AIT during childhood and adolescence, it suggested an association with earlier onset of clinical disease in children to enterovirus IgM-seropositive mothers.

Islet autoantibodies in cord blood from patients who developed type 1 diabetes mellitus at 15-30 years of age

Islet cell autoantibodies are early markers for type 1 diabetes. The aim of this study was to determine whether islet autoantibodies were present at birth in young adults who developed type 1 diabetes at 15-30 years of age. Cord blood sera from 30 patients who developed type 1 diabetes between 15 and 25 years of age and sera from 320 randomly selected control children were tested for islet cell antibodies (ICA) by indirect immunofluorescence and autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GADA), islet cell antigen-2 (IA-2A) and insulin (IAA) by radiobinding assays. The young adults who developed type 1 diabetes did not differ from controls in the cord blood prevalence of any of the four islet autoantibodies. This is in contrast to our previous findings that children who developed type 1 diabetes below 15 years of age had an increased prevalence of cord blood islet autoantibodies. Our present data suggest that, in contrast to children, pre- and perinatal risk factors are less likely to be involved in the development of type 1 diabetes in young adults.

Enterovirus infection during pregnancy is not a risk factor for celiac disease in the offspring

BACKGROUND

There is a strong genetic influence on the susceptibility to celiac disease but it is also evident that environmental factors play a role in the development of the disease. Diverging studies about adenovirus infection as a possible triggering factor in the pathogenesis have been reported. Our study was undertaken to determine whether enterovirus infection during pregnancy is a risk factor for the development of celiac disease later in childhood.

METHODS

Cord blood from 76 mothers whose children developed celiac disease before 15 years of age were analyzed for IgA, IgG, and IgM antibodies for enteroviruses and Ig-A endomysium antibodies. The control group comprised cord blood from 327 mothers with children without known celiac disease.

RESULTS

There were no significant differences in antibody titers for enterovirus between the two groups. IgA-endomysium antibodies were elevated in 3 of the 76 mothers, whereas none had known celiac disease.

CONCLUSION

This study does not show that enterovirus infection during pregnancy is associated with the development of celiac disease in childhood. Of the mothers whose children developed celiac disease, 4% had Ig-A endomysium antibodies, which may reflect a silent celiac disease.

Tissue transglutaminase autoantibodies and human leucocyte antigen in Down's syndrome patients with coeliac disease

The association between autoantibodies against tissue transglutaminase (tTG) and human leucocyte antigen (HLA)-DQB1 alleles was tested in Down's syndrome (DS) patients with and without coeliac disease (CD). Immunoglobulin A (IgA) and G (IgG) anti-tTG were measured in radioligand binding assays and compared with conventionally analysed IgA antibodies against gliadin (AGA) and IgA autoantibodies against endomysium (EMA) in 48 DS patients. HLA-DQB1 typing was carried out by polymerase chain reaction and hybridization with allele-specific probes in 41/48 patients. Both IgA-tTG and IgG-tTG, as well as EMA, were detected in 7/48 and AGA in 15/48 patients. Intestinal biopsy showed histopathological changes consistent with CD in 9/16 patients. HLA-DQB1 typing, available for 8/9 patients with and for 33/39 without CD, demonstrated that 5/8 with CD had DQB1*02 compared with 7/33 of those without (p = 0.0345). In patients with anti-tTG, 5/6 had the DQB1*02 allele compared with 7/35 of those without (p = 0.0053).

CONCLUSIONS

Anti-tTG are HLA-DQB1*02-associated autoantibodies which together could be useful screening tests for silent CD in DS patients. In patients with gastrointestinal symptoms or clinical signs of malabsorption, anti-tTG should be combined with AGA to detect other forms of enteropathies and CD.

Tissue transglutaminase autoantibodies and human leucocyte antigen in Down's syndrome patients with coeliac disease

The association between autoantibodies against tissue transglutaminase (tTG) and human leucocyte antigen (HLA)-DQB1 alleles was tested in Down's syndrome (DS) patients with and without coeliac disease (CD). Immunoglobulin A (IgA) and G (IgG) anti-tTG were measured in radioligand binding assays and compared with conventionally analysed IgA antibodies against gliadin (AGA) and IgA autoantibodies against endomysium (EMA) in 48 DS patients. HLA-DQB1 typing was carried out by polymerase chain reaction and hybridization with allele-specific probes in 41/48 patients. Both IgA-tTG and IgG-tTG, as well as EMA, were detected in 7/48 and AGA in 15/48 patients. Intestinal biopsy showed histopathological changes consistent with CD in 9/16 patients. HLA-DQB1 typing, available for 8/9 patients with and for 33/39 without CD, demonstrated that 5/8 with CD had DQB1*02 compared with 7/33 of those without (p = 0.0345). In patients with anti-tTG, 5/6 had the DQB1*02 allele compared with 7/35 of those without (p = 0.0053).

CONCLUSIONS

Anti-tTG are HLA-DQB1*02-associated autoantibodies which together could be useful screening tests for silent CD in DS patients. In patients with gastrointestinal symptoms or clinical signs of malabsorption, anti-tTG should be combined with AGA to detect other forms of enteropathies and CD.

An androgen receptor gene mutation (E653K) in a family with congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency as well as in partial androgen insensitivity

An androgen receptor (AR) variant (E653K) was found in two unrelated Swedish families. One family had two girls affected with congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency. The girls, who showed mild virilization in relation to their CYP21 genotype, had inherited the AR gene mutation from their father, who showed no symptoms of androgen insensitivity. The other family had a boy with partial androgen insensitivity and ambiguous genitalia, and he had inherited the AR gene mutation from his mother. The mutant receptor showed a transactivating capacity in the same range as the normal receptor at high concentrations of ligand (1 and 10 nM dihydrotestosterone), but absent or reduced transactivation at low levels (0.01 and 0.1 nM). The receptor variant was not found among 250 additional unselected Swedish men. Sequencing of the AR gene in five unrelated CAH girls with the I172N mutation in CYP21 and minimal virilization did not reveal any additional deviations from the normal reference sequence. In addition, there was no difference in lengths of the polymorphic CAG repeat in the AR gene between CAH girls with the I172N mutation who showed minimal and severe virilization, and we found no evidence of skewed X-inactivation. We conclude that AR gene mutations or polymorphisms are not a common factor influencing the degree of hyperandrogenic symptoms displayed by CAH girls, and that the AR E653K mutation is compatible with normal genital development, although it can cause genital malformations in susceptible individuals.

Low incidence of toxoplasma infection during pregnancy and in newborns in Sweden

To estimate the burden of disease due to congenital toxoplasmosis in Sweden the incidence of primary infections during pregnancy and birth prevalence of congenital toxoplasmosis in 40,978 children born in two regions in Sweden was determined. Women possibly infected during pregnancy were identified based on: 1, detection of specific IgG based on neonatal screening of the phenylketonuria (PKU) card blood spot followed by retrospective testing of stored prenatal samples to detect women who acquired infection during pregnancy and follow up of their children to 12 months: 2, detection of specific IgM on the PKU blood spot. The birth prevalence of congenital toxoplasmosis was 0.73/10,000 (95 % CI 0.15-2.14) (3/40,978). The incidence of primary infection during pregnancy was 5.1/10,000 (95% CI 2.6-8.9) susceptible pregnant women. The seroprevalence in the southern part was 25.7% and in the Stockholm area 14.0%. The incidence of infection during pregnancy was low, as the birth prevalence of congenital toxoplasmosis. Neonatal screening warrants consideration in view of the low cost and feasibility.

Prediction of silent celiac disease at diagnosis of childhood type 1 diabetes by tissue transglutaminase autoantibodies and HLA

AIMS

The aims were to estimate the diagnostic sensitivity and specificity of autoantibodies to tissue transglutaminase (IgA- and IgG-tTG), gliadin (AGA) and endomysium (EMA) in relation to human leukocyte antigen (HLA)-DQB1 alleles to identify silent celiac disease at diagnosis of type 1 diabetes.

METHODS

IgA- and IgG-tTG were measured in radioligand binding assays in 165 type 1 diabetic patients. Data on HLA-DQB1 were available for 148 patients and on both AGA and EMA for 164 patients. For patients considered positive for AGA or EMA, or both, an intestinal biopsy was suggested. HLA-DQB1 typing was carried out by polymerase chain reaction and hybridization with allele specific probes.

RESULTS

Three patients, left out from further study of antibodies, but not from HLA-DQB1 analysis, had treated celiac disease at diagnosis. Out of the other 162 type 1 diabetic patients tested, nine had IgA-tTG, six IgG-tTG, eight EMA, and 11 AGA. Biopsy was suggested for nine patients, of whom six showed villous atrophy, one did not and two refused to participate. Thus, silent celiac disease was probable in 8/162 and biopsy-verified in 6/162, where five patients were AGA-positive and six either EMA-, IgA-tTG- or IgG-tTG-positive. Of the 11 patients with celiac disease (three with treated and eight with silent celiac disease), 10 were HLA-DQB1-typed, of whom 65% (13/20) had the DQB1*02 allele, compared with 36% (100/276; p = 0.011) of those without celiac disease. IgA-tTG levels were higher in patients having either *02 or *0302 (0.6; -1.3-112.4 RU) compared with those not having these alleles (0.4; -0.7-3.4 RU; p = 0.023).

CONCLUSION

IgA-tTG are HLA-DQB1*02-associated autoantibodies with high sensitivity and specificity for silent celiac disease at diagnosis of type 1 diabetes.

Comparison of some different methods for analysis of thyroid autoantibodies: importance of thyroglobulin autoantibodies

Blood samples from 141 children and adolescents were used to evaluate differences between commercial kits and radioimmunoassay (RIA) methods for detecting thyroid autoantibodies. Thyroglobulin autoantibodies (Tg-Ab) were analyzed with a hemagglutination kit and a RIA; thyroid peroxidase autoantibodies (TPO-Ab) were measured with a gelagglutination assay and a RIA. The results of the antibody tests were compared with thyroid function tests (triiodothyronine [T3], thyroxine [T4], thyrotropin [TSH]) and with the results of ultrasound of the thyroid in antibody-positive patients. The correlation of antibody levels between the two methods was higher for TPO-Ab than for Tg-Ab. Moderate to high levels of TPO-Ab correlated to elevated TSH levels. Autoimmune thyroiditis (AIT) was found in 6 of the 141 children. The RIA-based thyroglobulin assay was the only test that identified autoantibodies in all 6 cases. In contrast, the hemagglutination kit thyroglobulin assay failed to identify 4 of the 6 AIT cases.

Functional consequences of mutations in the MODY4 gene (IPF1) and coexistence with MODY3 mutations

AIMS/HYPOTHESIS

The aim of this study was to examine the putative role of mutations in the insulin promoter 1 (IPF1) gene in early-onset diabetes.

METHODS

We carried out mutation screening of the IPF1 gene in 115 Scandinavian families with at least two members with onset of diabetes younger than 40 years. The allele frequencies were also tested in 183 unrelated patients with late-onset Type II (non-insulin-dependent) diabetes mellitus and in 92 non-diabetic control subjects.

RESULTS

Two novel IPF1 variants (G212R and P239Q) and one previously reported (D76N) IPF1 variant were identified in the 115 families (3.5%). The D76N variant was found in one MODY3 family (S315fsinsA of HNF1alpha) and also in two families with late-onset Type II diabetes. The P239Q variant was identified in two families with early-onset diabetes including one with MODY3 (R272C of HNF1alpha) and in three families with late-onset Type II diabetes. Despite the fact that the variants did not segregate completely with diabetes, the non-diabetic carriers of the IPF1 variants had increased blood glucose concentrations (p < 0.05) and reduced insulin:glucose ratios (p < 0.05) during an oral glucose tolerance test compared with non-diabetic family members without these variants. In addition, when the G212R and P239Q variants were expressed in cells without IPF1 i.e.. Nes2y cells, both variants showed about a 50% reduction in their ability to activate insulin gene transcription compared to wild-type IPF1, as measured by reporter gene assay.

CONCLUSION/INTERPRETATION

Although mutations in the IPF-1 gene are rare in early- (3.5 %) and late-onset (2.7 % ) Type II diabetes, they are functionally important and occur also in families with other MODY mutations.

Serological screening for celiac disease in healthy 2.5-year-old children in Sweden

OBJECTIVE

The study was designed to investigate the prevalence of celiac disease (CD) among 2.5-year-old children in a Swedish urban population with a high incidence of CD.

MATERIAL AND METHODS

Six hundred ninety apparently healthy children, born in the 12-month period of July 1992 through June 1993, were screened for immunoglobulin A (IgA) antigliadin antibodies and IgA antiendomysium antibodies, and those antibody-positive at repeated testing were further investigated with intestinal biopsy.

RESULTS

Of the 690 children, 6 were both IgA antigliadin antibody- and IgA antiendomysium antibody-positive, and 7 were antiendomysium antibody-positive but antigliadin antibody-negative. Jejunal biopsy, performed in 12 cases, manifested partial or total villous atrophy in 8 cases. Thus, together with an additional child whose parents declined the offered biopsy, but whose response to a gluten-free diet confirmed the presence of CD, the prevalence of CD in the study series was 1.3% (9/690; 95% confidence interval:.4-2.2). However, independent of the study, an additional 22 cases of symptomatic, biopsy-verified CD have already been detected in the birth cohort of 3004 children.

CONCLUSIONS

The prevalence of CD in our study series was high, at least 1.0%, but may be as high as 2.0% if the frequency of silent CD is as high as we have found in the remaining unscreened cohort. These findings confirm that CD is one of the most common chronic disorders.

Mutations in short stature homeobox containing gene (SHOX) in dyschondrosteosis but not in hypochondroplasia

Dyschondrosteosis (DCO) and hypochondroplasia (HCH) are common skeletal dysplasias characterized by disproportionate short stature. The diagnosis of these conditions might be difficult to establish especially in early childhood. Point mutations and deletions of the short stature homeobox containing gene (SHOX) are detected in DCO and idiopathic short stature with some rhizomelic body disproportion, whereas mutations in the fibroblast growth factor receptor 3 (FGFR3) gene are found in 40-70% of HCH cases. In this study, we performed mutational analysis of the coding region of the SHOX gene in five DCO and 18 HCH patients, all of whom tested negative for the known HCH-associated FGFR3 mutations. The polymorphic CA-repeat analysis, direct sequencing and Southern blotting were used for detection of deletions and point mutations. The auxological and radiological phenotype of these patients was carefully determined. Three novel mutations in DCO patients were found: (1) a deletion of one base (de1272G) (according to GenBank accession nos. Y11536, Y11535), resulting in a premature stop codon at position 75 of the amino acid sequence; (2) the transversion C485G resulting in the substitution Leu132Val; and (3) the transversion G549T causing an Arg153Leu substitution. These substitutions segregate with the DCO phenotype and affect evolutionarily conserved homeodomain residues, based on a comparison of homeobox containing proteins in 13 species. Moreover, these changes were not found in 80 unrelated, unaffected individuals. This strongly suggests that these mutations are pathogenic. The phenotype of our patients with DCO and HCH varied from mild to severe shortness and body disproportion. These results further support clinical and genetic heterogeneity of dyschondrosteosis and hypochondroplasia.

Prevalence of beta-cell and thyroid autoantibody positivity in schoolchildren during three-year follow-up

The prevalence of autoantibodies against the 65 kD isoform of glutamic acid decarboxylase (GAD65Ab), insulin (IAA), islet cells (ICA), thyroid peroxidase (TPOAb) and thyroglobulin (TgAb), in relation to HLA-DR types, was assessed in 310 (HLA in 280) twelve-year-old children during three-year follow-up. Altogether, 26.8% (83/310) of the children were found to carry at least one autoantibody. The HLA-DR3/DR4 genotype was significantly more prevalent in the subgroup of children GAD65Ab-positive on at least one occasion than among GAD65Ab-negative children [33% (2/6) vs. 5% (12/274); p = 0.031, as was the HLA-DR4/x genotype among children seropositive for at least one thyroid autoantibody, compared to the corresponding seronegative subgroup 152% (34/65) vs. 34% (74/215); p=0.01]. The proportion of children seropositive in at least one of the three tests was 1.9% (6/310) for GAD65Ab, 2.6% (8/310) for IAA, 5.2% (16/310) for ICA, 11.3% (35/310) for TPOAb and 19.4% (60/310) for TgAb. All autoantibodies except GAD65Ab tended to disappear during follow-up, and at the three-year follow-up IAA had disappeared in 50% (2/4) of cases, ICA in 67% (6/9), TPOAb in 30% (6/20) and TgAb in 38% (18/47) of cases. The turnover of seropositive subjects and the large proportion of children seropositive for at least one islet or thyroid autoantibody during a three-year follow-up suggest transient autoantibodies to be more common than is discernible in cross-sectional investigations.

Management of males with 45,X/46,XY gonadal dysgenesis

Males with the 45,X/46,XY karyotype and malformations of the external genitalia carry an increased risk of developing germ cell neoplasia of the gonads. We have studied gonadal tissue from 10 individuals, 0.3-17 years of age, with a male phenotype and either hypospadias and/or cryptorchidism. Four patients, 0.3-15 years of age, had carcinoma in situ, 1 boy had Sertoli-cell-only pattern and the remainder prepubertal histology. Gonadoblastoma or invasive carcinoma was not found. On the basis of our current knowledge we propose a strategy for management and follow-up of these boys in order to detect possible premalignant histological changes early and prevent development of a gonadal tumour.

Report on a long-term study of maternal and congenital cytomegalovirus infection in Sweden. Review of prospective studies available in the literature

This report summarizes knowledge accumulated in a long-term study of congenital and maternal cytomegalovirus (CMV) infection in Sweden. Some new findings are included. We considered diagnostic methods, sources of maternal infection (including occupational risks), roles of primary and secondary maternal infections, transmission to foetuses, incidence, symptoms and prognosis of established congenital infection and relative importance of such infection in infantile sensorineural deafness, microcephaly and type 1 diabetes mellitus. Virus isolation testing was done 1977-1985 on 16,474 newborns. 76 (0.5%) congenitally infected infants were found, 22/76 (29%) with transient neonatal symptoms and 11/60 (18%) with neurological symptoms by the age of 7 y. Type of maternal CMV infection was serologically determined in 62/76 cases (30 primary, 32 secondary). CNS disturbances in the infants occurred after both primary (all trimesters) and secondary maternal infections. The negative potential of secondary maternal infections might be an obstacle to preventive vaccination.

Prevalence of coeliac disease in Turner syndrome

This study was undertaken to investigate the prevalence of coeliac disease in children and adolescents with Turner syndrome. Eighty-seven children and adolescents with Turner syndrome were screened for IgA-antiendomysium antibodies (EMA) and IgA-antigliadin antibodies (AGA), 5% (4/87) being found to be EMA-positive, and 15% (13/87) to have AGA levels above normal. Of the 10 patients who were either AGA- or EMA-positive and further investigated with intestinal biopsy, four manifested villous atrophy (i.e. all three of the EMA-positive patients, but only one of the seven AGA-positive patients). The results suggest EMA-positivity to be a good immunological marker for use in screening for coeliac disease, and such screening to be justified in patients with Turner syndrome.

High frequency of mutations in MODY and mitochondrial genes in Scandinavian patients with familial early-onset diabetes

AIMS/HYPOTHESIS

To investigate the contribution of mutations in maturity-onset diabetes of the young (MODY) and mitochondrial genes to early-onset diabetes with a strong family history of diabetes in a cohort with a high prevalence of Type I (insulin-dependent) diabetes mellitus.

METHODS

Screening for sequence variants in the hepatocyte nuclear factor (HNF)-4alpha (MODY1), glucokinase (MODY2), HNF-1alpha (MODY3) genes and mitochondrial DNA was carried out in 115 Finnish and Swedish patients with early-onset ( </= 40 years) diabetes using the single strand conformation polymorphism (SSCP) technique and direct sequencing. Allele frequencies were compared with 118 patients with onset of diabetes Type II (non-insulin-dependent) diabetes mellitus after the age of 40 and 92 non-diabetic control subjects without a family history of diabetes.

RESULTS

In total 52 sequence variants were found in the HNF-1alpha, HNF-4alpha and glucokinase genes, 12 of which were considered as MODY mutations. Three families had the A3243G mutation in the mitochondrial tRNA(Leu) gene, which resulted in an overall prevalence of these mutations of 13 %.

CONCLUSION/INTERPRETATION

Among 115 Scandinavian families, mutations in the HNF-1alpha gene represented the most common cause of familial early-onset ( </= 40 years) diabetes: MODY3 (5.2 %) more than MODY2 (3.5 %) more than MIDD (2.6 %) more than MODY1 (1.7 %).

Previous exposure to measles, mumps, and rubella--but not vaccination during adolescence--correlates to the prevalence of pancreatic and thyroid autoantibodies

OBJECTIVE

This study was designed to determine whether a relationship exists between previous exposure to measles, mumps, and rubella (MMR) by natural infection or vaccination or by new immunization with MMR vaccine, and either the presence or levels of autoantibodies against thyroid cell and pancreatic beta-cell antigens.

METHODS

Antibodies against MMR and autoantibodies against thyroglobulin, thyroid peroxidase, pancreas islet cells (ICA), islet cell surface, glutamic acid decarboxylase 65k autoantibodies, and insulin were studied before, and 3 months after, vaccination with combined MMR vaccine in 386 school children between 11 and 13 years of age.

RESULTS

The vaccination changed neither the prevalence nor the level of autoantibodies. Children with rubella antibodies before vaccination had higher levels of ICA than did the rubella seronegative children. In contrast, thyroid autoantibody levels and prevalence were lower in children with antibodies against measles, mumps, or both before vaccination than in children without those antibodies.

CONCLUSIONS

Previous natural infection or vaccination against measles, mumps, or both seemed to have an inhibitory effect on the development of thyroid autoantibodies. In contrast, children with previous exposure to rubella had higher levels of ICA. No evidence was found that MMR vaccination during adolescence may trigger autoimmunity.