International consensus on the diagnosis and management of pediatric patients with hereditary angioedema with C1 inhibitor deficiency

Background

The consensus documents published to date on hereditary angioedema with C1 inhibitor deficiency (C1‐INH‐HAE) have focused on adult patients. Many of the previous recommendations have not been adapted to pediatric patients. We intended to produce consensus recommendations for the diagnosis and management of pediatric patients with C1‐INH‐HAE.

Methods

During an expert panel meeting that took place during the 9th C1 Inhibitor Deficiency Workshop in Budapest, 2015 (www.haenet.hu), pediatric data were presented and discussed and a consensus was developed by voting.

Results

The symptoms of C1‐INH‐HAE often present in childhood. Differential diagnosis can be difficult as abdominal pain is common in pediatric C1‐INH‐HAE, but also commonly occurs in the general pediatric population. The early onset of symptoms may predict a more severe subsequent course of the disease. Before the age of 1 year, C1‐INH levels may be lower than in adults; therefore, it is advisable to confirm the diagnosis after the age of one year. All neonates/infants with an affected C1‐INH‐HAE family member should be screened for C1‐INH deficiency. Pediatric patients should always carry a C1‐INH‐HAE information card and medicine for emergency use. The regulatory approval status of the drugs for prophylaxis and for acute treatment is different in each country. Plasma‐derived C1‐INH, recombinant C1‐INH, and ecallantide are the only agents licensed for the acute treatment of pediatric patients. Clinical trials are underway with additional drugs. It is recommended to follow up patients in an HAE comprehensive care center.

Conclusions

The pediatric‐focused international consensus for the diagnosis and management of C1‐INH‐HAE patients was created.

NSD1 duplication in Silver-Russell syndrome (SRS): molecular karyotyping in patients with SRS features

Silver-Russell syndrome (SRS) is a growth retardation syndrome characterized by intrauterine and postnatal growth retardation, relative macrocephaly and protruding forehead, body asymmetry and feeding difficulties. Nearly 50% of cases show a hypomethylation in 11p15.5, in 10% maternal uniparental disomy of chromosome 7 is present. A significant number of patients with SRS features also exhibit chromosomal aberrations. We analyzed 43 individuals referred for SRS genetic testing by molecular karyotyping. Pathogenic variants could be detected in five of them, including a NSD1 duplication in 5q35 and a 14q32 microdeletion. NSD1 deletions are detectable in overgrowth disorders (Sotos syndrome and Beckwith-Wiedemann syndrome), whereas NSD1 duplications are associated with growth retardation. The 14q32 deletion is typically associated with Temple syndrome (TS14), but the identification of a patient in our cohort reflects the clinical overlap between TS14 and SRS. As determination of molecular subtypes is the basis for a directed counseling and therapy, the identification of pathogenic variants in >10% of the total cohort of patients referred for SRS testing and in >16% of characteristic individuals with the characteristic SRS phenotype confirms the need to apply molecular karyotyping in this cohort.

Potential advantage of N363S glucocorticoid receptor polymorphism in 21-hydroxylase deficiency

OBJECTIVE

Congenital adrenal hyperplasia (CAH) shows a range of severity which is explained in part by the different mutations of the CYP21 gene. To better understand the incomplete concordance between genotype and phenotype in CAH the role of the sensitizing N363S polymorphism of the glucocorticoid receptor (GR) was examined in CAH patients.

DESIGN

CAH patients were screened for N363S. Laboratory findings and clinical characteristics of carriers and non-carriers were analyzed retrospectively.

METHODS

The CYP21 gene of 200 CAH patients was analyzed by allele-specific PCR. The GR gene was tested for N363S by PCR followed by restriction fragment length polymorphism. Antropometric data (height, weight), degree of intrauterine virilization, hormone concentrations (17-OH-progesterone, dehydroepiandrosterone (DHEA), aldosterone, testosterone, plasma renin activity), substitution doses and clinical course were analyzed.

RESULTS

The carrier frequency of N363S in CAH patients was equivalent to that of the general Hungarian population (6% vs 7.8%). Interestingly, none of the non-classical CAH (NC-CAH) patients were carriers of the polymorphism. Carrier girls had milder genital virilization than mutation-matched non-carrier controls. There was no significant difference between the carriers and non-carriers in either the substitution doses, the hormonal, or the auxiological parameters.

CONCLUSIONS

The association of sensitizing the GR variant with impaired cortisol production in CAH might be compensatory in mild NC-CAH and may prevent severe intrauterine virilization in classical form. Although the exact role of N363S in extrauterine life should be further investigated, the consideration of certain genetic polymorphisms of CAH patients may lead to better, individualized therapeutic regimes.

[Latent autoimmune diabetes in adults(LADA): part of the clinical spectrum of type-1 diabetes mellitus of autoimmune origin]

According to the most recent classification of diabetes mellitus the latent autoimmune diabetes in adults belongs to the group of type 1 autoimmune diabetes mellitus, as a slowly progressive form. It is not clear whether LADA is a distinct clinical entity or it is a part of the clinical spectrum of type 1 diabetes mellitus. The authors compare the antropologic (body mass index, waist to hip ratio), immunologic (occurrence of islet cell cytoplasmic autoantibodies and autoantibodies against glutamic acid decarboxylase and tyrosin phosphatase), genetic (HLA DR and DQ alleles known to be associated to type 1 diabetes mellitus) characteristics and occurrence of the features of the metabolic syndrome in the groups of type 1 and type 2 diabetes and LADA. 81 type 1 and 190 type 2 diabetics and 38 LADA patients were involved into the study. Freshly diagnosed type 1 diabetics served for controls of the autoantibody study: 48 patients manifested < or = 16 years of age and 89 type 1 diabetics manifested above 16 years of age. The three main diabetic groups differed in age: the average age in the type 1, type 2 and LADA groups were 37, 63 and 58 years respectively. There was no difference among the three groups in gender. The duration of the disease differed significantly between the type 2 and LADA groups (4.0 and 8.0 years respectively). In spite of the shorter duration of the disease in the LADA group, compared to the type 2 diabetics the frequency of insulin dependency was significantly higher in the LADA (81.6%) than in the type 2 group (46.7%). The BMI and WHR were comparable between the type 1 and LADA patients (average values were 23 and 0.83 in type 1 patients and 23.25 and 0.89 in LADA). The type 2 group differed significantly from type 1 and LADA (average values were 29.1 and 0.5). The concentration of glycated hemoglobin was comparable in the three groups. But there was a significant difference in HbA1c concentration between the freshly diagnosed subgroups of type 1 and LADA patients: 10.85% and 8% respectively. The fasting C-peptid levels were significantly higher in the sera of type 2 diabetics (0.75 pmol/l) compared to type 1 (0.2 pmol/l) and LADA patients (0.29 pmol/l). There was a significant difference in C-peptid concentrations between the type 1 and LADA groups, too. The insulin deficiency in LADA seemed to be not as severe as in type 1 diabetes. The serum total cholesterol and triglyceride levels were significantly higher and the HDL cholesterol concentration significantly lower in type 2 diabetics comparing to type 1 and LADA patients and there was no significant difference in this respect between the type 1 and LADA groups. The frequency of occurrence of hypertension differed no significantly between type 2 and LADA, but that of in type 1 diabetes was significantly lower than both type 2 and LADA. The occurrence of multiple autoantibodies (ICA + GADA + anti-IA2) was much more frequent in type 1 diabetes compared to LADA. In the sera of LADA patients the occurrence of ICA and GADA alone or ICA + GADA was characteristic (31.5% - 21.1% - 15.8% respectively). There was no difference between type 1 diabetes and LADA in the occurrence of the alleles of the MHC kown to be associated with type 1 diabetes. The occurrence of the haplotypes HLA DQ2/DR3 and/or DQ8/DR4 was observed in two thirds of type 1 diabetic and LADA patients. Chronic diabetic complications were observed in all of the groups and there was only a secondary connection of the complications with the type of the diabetes. Based on the results the authors suggest that LADA is a part of the clinical spectrum of type 1 diabetes of autoimmune origin.

[High prevalence of islet cell and glutamate decarboxylase antibodies in healthy young adults born with low birth weight]

Low birth weight is an independent risk factor for several chronic adult diseases. The authors determined the prevalence of islet cell cytoplasmatic antibody (ICA), glutamic acid decarboxylase antibody (GADA) and tyrosine phosphatase antibody (IA2) in 41 women and 34 men born with a birth weight under 2500 grams. ICA and/or GADA positivity was detected in 32% of the subjects tested. Both antibodies were present in 11% of the subjects. IA2 positivity was not found in any of the enrolled subjects. The cause of the high prevalence of autoantibodies is still unclear. Further studies are needed to elucidate whether this phenomenon might have a role in the development of metabolic disturbances in late adulthood.

[Diabetic ketoacidosis in childhood]

Diabetic ketoacidosis is the most serious acute complication of insulin-dependent diabetes mellitus and the most frequent reason for hospital admission of diabetic children. The most frequent cause of death of these patients is also the diabetic ketoacidosis. The mortality rate of the disease has not changed since the seventies (1-2%). In this work, the data of 89 patients with diabetic ketoacidosis were analyzed. These patients were admitted to the 1. Department of Pediatrics of the Semmelweis University of Medicine between 1992-1997. The data (metabolic parameters, the causes of ketoacidosis and the length of hospital stay) of previously known diabetic children was compared with the data of previously unknown diabetic children. Our patients were divided in 2 groups: serious (n = 11), and mild-to-moderate (n = 48) acidosis. Their laboratory findings, their intravenous infusion-, and insulin demand and the length of their hospital stay were compared. The state of consciousness at their hospitalisation and the concomitant complications were also examined. Significant difference was found only in the duration of intravenous insulin administration (with the exception of pH and BE, of course). There was no relationship between the seriousness of the disease and the duration of hospital treatment. It is noteworthy that even the previously known diabetic children with the shortest hospitalization spent more than 7 days at the department.

[Detection of antibodies against pancreatic islet cells in clinical practice]

Development of diabetes mellitus caused by pancreatic beta-cell destruction of autoimmune origin is the result of a long lasting process. The most easily examinable feature of this stage is the occurrence of the islet cell antibodies. The sera which are positive for islet cell cytoplasmic antibodies (ICA), examined by indirect immunofluorescence, contain a mixture of antibodies. The glutamic acid decarbocylase (GAD), the tyrosin phosphatase (IA2), the insulin, and the GM2-1 glycolipid can be the targets of these antibodies. One can routinely examine the ICA, the GADA, the IA2 antibodies. The detection of antibodies against insulin (IAA) and GM-2-1 glycolipid is not invented in the routine laboratory work. The aim of the authors was the evaluation of clinical significance of occurrence of islet cell antibodies: one hundred and eighteen nondiabetic children an adult human being without known diabetic first degree relatives and 366 type 1 diabetic children and adult patients served as controls. The authors evaluated the predictive value of the different islet cell antibodies to the development of type 1 diabetes mellitus in 596 nondiabetic children with type 1 diabetic first degree relatives. The authors looked for markers of beta-cell destruction among sera of 320 diabetics manifested after 30 years of age with at least half a year of non-insulin-dependency and in the sera of 68 females suffered from gestational diabetes after 0-14 years of the index pregnancy. Finally the authors report 7 cases in which the examination of islet cell antibodies helped the diagnosis and classification of diabetes mellitus. Indirect immunofluorescence method was used for the detection of ICA, radioimmunoassay for that of GADA and IA2 antibodies. There was no positive reaction for ICA and GADA in the nondiabetic population without diabetic first degree relatives. Among the freshly diagnosed type 1 diabetic children 39% were positive for only ICA, 44% for only GADA and 80% for any antibodies. Among the freshly manifested type 1 diabetic adults ICA positivity only was observed in 21%, GADA positivity only in 7.1% and 93% for any antibodies. From the 595 nondiabetic children with type 1 diabetic first degree relatives 23 were positive for ICA, from whom 5 became diabetic during a two years observation period. These diabetic children had multiplex autoantibodies besides ICA. One child from this group, who was negative for ICA became diabetic, too. Among type 2 diabetic patients 13% were positive for ICA alone, 17% were positive for GADA alone and 27% were positive for any antibodies. The insulin dependency manifested in a short time was associated with antibody positivity. Among the gestational diabetics 10 were found positive for ICA. From them, 7 were type 1 diabetics, and 3 were type 2 diabetics at the time of the detection of antibodies. The authors suggest the need of determination of islet cell antibodies in the group of nondiabetic first degree relatives of type 1 diabetic patients (ICA, GADA, IA2 and IAA), in the group of non-insulin-dependent diabetics (ICA and GADA) as a screening for later insulin dependency, and in gestational diabetes after delivery (ICA) as screening for type 1 diabetes mellitus.

Sodium-lithium countertransport in children with nephrotic syndrome

The mechanisms of sodium retention in edema-forming minimal change nephrotic syndrome (MCNS) have not been completely evaluated. The aim of this study was to characterize the transmembrane sodium transport in nephrotic syndrome by measuring the erythrocyte sodium-lithium countertransport (SLC) in vitro. Eighteen children with MCNS were studied in the edema-forming state, and subsequently at the beginning of remission. Nephrotic children with edema retained sodium (10+/-12 micromol/day) and had a higher SLC [426+/-118 vs. 281+/-60 micromol/l red blood cells (RBC) per hour, P=0.003). The intracellular sodium concentration of nephrotics was 6.1+/-2.1 mmol/l RBC, which did not differ from that of controls (6.42+/-2.24, n=13). In remission sodium balance became negative (-30+/-21 mmol/day), and the SLC decreased but still differed significantly from control values (P=0.009). The intracellular sodium content decreased to 4.4+/-0.9 mmol/l RBC (P=0.002). There was a negative correlation between erythrocyte SLC and plasma albumin concentration (r=0.48, P=0.003), and urinary sodium excretion rate (r=0.66, P=0.001). In conclusion, erythrocyte SLC is high in the edema-forming state of childhood nephrotic syndrome and decreases with the onset of remission. A role for the SLC in the altered sodium homeostasis of nephrotic syndrome is suggested.

Altered erythrocyte sodium-lithium counter-transport and Na+/K(+)-ATPase activity in cystic fibrosis

Patients with cystic fibrosis (CF) exhibit normal concentrations of sodium and chloride in spite of the disturbance of Cl- and Na+ transport in epithelial cells. To characterize compensatory mechanisms in the regulation of sodium homeostasis, erythrocytes of 13 CF patients were analysed for sodium-lithium counter-transport (SLC), Na+/K(+)-ATPase activity and intracellular sodium content. Values were compared to those of healthy controls. Patients with CF had normal serum sodium and chloride concentrations and renal excretions of these ions were within the physiological range. Intracellular sodium concentration was similar in the CF and the control group (6.8 +/- 2.2 vs 5.7 +/- 1.0 mmol/l RBCs). Red blood cells' SLC and Na+/ K(+)-ATPase activity were elevated in CF patients (381 +/- 106 mumol/h/l RBCs vs 281 +/- 64; p < 0.01) and (445 +/- 129 mumol ATP mg prot/h vs 322 +/- 84, p < 0.01). Our study demonstrates that transmembrane cation transport systems are highly activated in CF. The increased sodium transport may be part of a compensatory mechanism of sodium homeostasis in children with CF.