Next-generation sequencing reveals deep intronic cryptic ABCC8 and HADH splicing founder mutations causing hyperinsulinism by pseudoexon activation.

Next-generation sequencing (NGS) enables analysis of the human genome on a scale previously unachievable by Sanger sequencing. Exome sequencing of the coding regions and conserved splice sites has been very successful in the identification of disease-causing mutations, and targeting of these regions has extended clinical diagnostic testing from analysis of fewer than ten genes per phenotype to more than 100. Noncoding mutations have been less extensively studied despite evidence from mRNA analysis for the existence of deep intronic mutations in >20 genes. We investigated individuals with hyperinsulinaemic hypoglycaemia and biochemical or genetic evidence to suggest noncoding mutations by using NGS to analyze the entire genomic regions of ABCC8 (117 kb) and HADH (94 kb) from overlapping ~10 kb PCR amplicons. Two deep intronic mutations, c.1333-1013A>G in ABCC8 and c.636+471G>T HADH, were identified. Both are predicted to create a cryptic splice donor site and an out-of-frame pseudoexon. Sequence analysis of mRNA from affected individuals' fibroblasts or lymphoblastoid cells confirmed mutant transcripts with pseudoexon inclusion and premature termination codons. Testing of additional individuals showed that these are founder mutations in the Irish and Turkish populations, accounting for 14% of focal hyperinsulinism cases and 32% of subjects with HADH mutations in our cohort. The identification of deep intronic mutations has previously focused on the detection of aberrant mRNA transcripts in a subset of disorders for which RNA is readily obtained from the target tissue or ectopically expressed at sufficient levels. Our approach of using NGS to analyze the entire genomic DNA sequence is applicable to any disease.

Gastric carcinoid tumor in a 14-year old girl.

Gastric carcinoid tumors (GCT) are rare lesions that constitute 2.6-8.7% of all gastrointestinal carcinoids, mostly affect middle-aged females but the incidence in children is unknown. We present a 14-year-old girl, with GCT. She was treated with recombinant human growth hormone (GH) for complete GH deficiency, and endoscopy was performed to identify iron-deficiency anemia. Upper gastrointestinal endoscopy revealed a gastric polyp, and biopsies were compatible with GCT.

Adherence to growth hormone therapy: results of a multicenter study.

OBJECTIVE: To evaluate the adherence to growth hormone (GH) therapy and identify the influencing factors and outcomes in children. METHODS: A total of 217 GH-naïve patients in 6 pediatric endocrinology clinics were enrolled in the study. Structured questionnaires were filled out and patients were evaluated at the initiation and 3rd, 6th, and 12th months of therapy. Patients were categorized into 4 adherence segments based on percentage of doses omitted at each evaluation period, classified as excellent if 0%, good if 5%, fair if 5 to 10%, and poor if > 10%. RESULTS: There was a decrement in adherence to GH therapy during the study period (P = .006). Patients who showed excellent and good adherence to therapy had better growth velocity and growth velocity standard deviation scores (SDSs) (P = .014 and P = .015, respectively). A negative correlation between growth velocity SDS and number of missed injections was also observed (r = -.412; P = .007). A positive correlation between delta insulin-like growth factor-1 (IGF-1) SDS and growth velocity was demonstrated (r = .239; P = .042). IGF-1 levels were significantly higher in patients who showed excellent and good adherence to therapy (P = .01). Adherence was better in boys than in girls (P = .035), but adherence rates were not associated with age, cause of GH treatment, socioeconomic status, person who administered the injections, type of injection device, or GH product. CONCLUSION: Poor adherence to GH therapy was common in our group of patients and was one of the factors underlying suboptimal growth during therapy. Before considering other problems that can affect growth, clinicians should confirm good adherence to therapy.

Pathophysiology of critical illness hyperglycemia in children.

Causes of hyperglycemia in critically ill non-diabetic children may differ from those in adults. The objective of this study was to investigate the pathogenesis of critical illness hyperglycemia (CIH) in terms of insulin resistance and ß-cell dysfunction. Critically ill children with blood glucose (BG) levels of >150 mg/dL (8.3 mmol/L) were enrolled in the study. Insulin sensitivity and ß-cell function in the hyperglycemic and euglycemic periods were analyzed with BG/insulin and BG/C-peptide ratios, and utilizing homeostasis model assessment (HOMA). A total of 40 patients were enrolled in the study. BG/insulin and BG/C-peptide ratios were significantly higher in the hyperglycemic period. The HOMA-B and S scores for the hyperglycemic period revealed that out of all the patients who survived (n=30), 20 had ß-cell dysfunction, while the remaining (n=11) had insulin resistance. ß-cell dysfunction was significantly higher in the hyperglycemic period (p<0.001). As in adults, ß-cell dysfunction may play a major role in the pathophysiology of CIH in children.

The clinical and genetic heterogeneity of mixed gonadal dysgenesis: does "disorders of sexual development (DSD)" classification based on new Chicago consensus cover all sex chromosome DSD?

UNLABELLED: Clinical findings illustrate the wide spectrum of the phenotypic manifestations of 45,X/46,XY mosaicism in the sex chromosome disorders of sex differentiation (DSD). The objective of study is to evaluate the characteristics of 45,X/46,XY patients and questioning of their place within the DSD categorization. The clinical findings of 11 patients with 45,X/46,XY mosaicism are described including the presentation, gonadal morphology, genital anatomy, and the hormone levels among 285 patients with DSD evaluated. Sixty-seven patients were diagnosed with sex chromosome DSD (50 Turner, three Klinefelter, ten 45,X/46,XY gonadal disgenesis, one 45X/46,XY ovotesticular DSD, one 47,XYY ovotesticular DSD, and two 46,XX/46,XY ovotesticular DSD). The type and the percentage of patients with 45,X/46,XY mosaicism were as follows: Four cases of mix gonadal dysgenesis, four cases of partial gonadal dysgenesis, two cases of complete gonadal dysgenesis, one case of ovotesticular DSD. On the other hand, another patient that has 45,X/46,XX mosaicism was diagnosed with MGD with the presence of the streak gonad on the right side and the testis on the other side. CONCLUSION: We suggest that sex chromosome DSD categorization can include 45,X/46,XY PGD and 45,X/46,XY CGD. Mixed gonadal dysgenesis may be also placed among the disorders of testicular differentiation of 46,XY DSD subdivision.

Contribution of clinical, metabolic, and genetic factors on hypertension in obese children and adolescents.

The role of ACE gene insertion (I) or deletion (D) polymorphism on blood pressure phenotype is not clear in children. The aim of this work is to examine the association between hypertension and ACE I/D polymorphism, as well as the contribution of clinical and metabolic parameters on blood pressure. The study participants were 199 obese children. Forty-four of them were hypertensive. The hypertensive subjects were older than the normotensive and most of them were pubertal. The prevalence of hypertension in obese subjects with II, ID, and DD genotype was similar. There was no difference between the hypertensive and the normotensive group according to ACE I/D genotype, BMISDS, sex, blood glucose level and total cholesterol levels. In obese children, high IR-HOMA values, puberty, presence of family history for hypertension, hypertriglyceridemia, and low HDL-cholesterol, high triglyceride/HDL-cholesterol ratio were found as increased risk factors of hypertension. In obese children and adolescents, blood pressure did not differ by ACE I/D genotype. The presence of family history, puberty, insulin resistance and hypertriglyceridemia constitute important risk factors for developing hypertension.

The endocrine spectrum of intracranial cysts in childhood and review of the literature.

Intracranial cysts (ICC) may cause a wide spectrum of endocrinological disorders. We evaluated 27 patients who were diagnosed with ICC during investigation for neuroendocrine dysfunctions and reviewed the relevant literature. The types of ICC in the patients were arachnoid cysts (n = 13); Rathke cleft cysts (n = 7); pineal cysts (n = 5); an ependymal cyst (n = 1) and a cavum septum pellucidum cyst (n = 1). The neuroendocrine dysfunctions of the patients were obesity (n = 7), isolated growth hormone deficiency (n = 6), central precocious puberty (n = 6), multiple pituitary hormone deficiency (n = 3), central diabetes insipidus (n = 1), growth hormone deficiency and central precocious puberty (n = 1), obesity and galactorrhea (n = 1), obesity and hypogonadotropic hypogonadism (n = 1) and growth hormone neurosecretory dysfunction (n = 1). Only three patients, who had arachnoid cysts, showed neurologic symptomatology. Although three patients underwent surgery, no improvements in endocrinological dysfunctions were observed. ICC should be considered when evaluating patients with endocrinological problems and patients with coincidental ICC should be recommended for follow-up.

Characteristics and prevalence of non-classical congenital adrenal hyperplasia with a V2811 mutation in patients with premature pubarche.

We aimed to determine the prevalence and clinical characteristics of non-classical congenital adrenal hyperplasia (NCCAH) with V281L mutation in patients with premature pubarche. An adrenocorticotrophic hormone (ACTH) stimulation test was performed in 14 of the 159 patients with premature pubarche (PP). Patients whose stimulated 17alpha-hydroxyprogesterone (17-OHP) level on the ACTH test was > or =10 ng/mL underwent a mutational analysis of the CYP21 gene. NCCAH was defined in nine (5.7%) patients, all of whom had the V281L mutation. Four of the NCCAH patients were homozygote and four of them were heterozygote. One other patient was compound heterozygote for V281L mutation and the I2 splice mutation. One of the patients with V281L heterozygous mutation developed true precocious puberty and the other one had rapid progressive early puberty and developed polycystic ovary syndrome. ACTH stimulated 17-OHP > or = 10 ng/mL in PP patients is load star to mutation analysis and heterozygote patients should be followed for clinical and biological hyperandrogenism up to completion of the whole 'genome sequence'.

Primary adrenal insufficiency in a child after busulfan and cyclophosphamide-based conditioning for hematopoietic stem cell transplantation.

High rates of skeletal complications, growth disturbances, thyroid and gonadal dysfunction have been described in children undergoing stem cell transplantation. Although secondary adrenal insufficiency has been diagnosed, no primary adrenal insufficiency has been reported after busulfan and cyclophosphamide (Bu/Cy)-based conditioning regimens for stem cell transplantation in children. A 9-year-old girl with myelodysplastic syndrome was treated with stem cell transplantation of allogeneic origin. She received myeloablative conditioning chemotherapy, Bu and Cy. Her serum cortisol level was normal before stem cell transplantation. Then, 17 months after stem cell transplantation, chronic graft-versus-host disease developed and was treated with methyl prednisolone for 3 months. The control endocrinological investigation revealed low serum cortisol and high serum adrenocorticotropin (ACTH) levels 6 months after completion of methyl prednisolone treatment. The ACTH stimulation test demonstrated primary adrenal insufficiency, and the other etiologies of primary adrenal insufficiency were excluded. The patient received oral prednisolone replacement therapy. She was followed-up for 44 months and required increases in steroid doses during stress periods. Primary adrenal insufficiency which was observed in our patient after Bu/Cy-based conditioning regimen for stem cell transplantation has not been reported in children and adrenal function should be closely monitored in these patients both before stem cell transplantation and after stem cell transplantation.

Clinical characteristics of recessive and dominant congenital hyperinsulinism due to mutation(s) in the ABCC8/KCNJ11 genes encoding the ATP-sensitive potasium channel in the pancreatic beta cell.

BACKGROUND: Recessive mutations in ABCC8/KCNJ11 of beta-cell K(ATP) channel generally cause severe medically unresponsive hyperinsulinemic hypoglycemia (HH). Rarer dominant mutations in these genes have been described that mostly cause milder, medically responsive congenital hyperinsulinism. Rarer dominant mutations in these genes have been described that mostly cause milder, medically responsive congenital hyperinsulinism. To date the phenotype of patients with dominant mutations seems to be different from those with recessive mutations as the majority of patients are responsive to diazoxide therapy. Controversy exists on whether these dominant ABCC8 or KCNJ11 genes mutations predispose to diabetes mellitus in adulthood or not. SUBJECTS: We report the clinical and genetic characteristics of five patients with neonatal HH, three had recessively inherited K(ATP) channel mutations and two with a dominantly acting mutation. As a result of failure to medical therapy, patients with recessive K(ATP) channel mutations underwent a near total pancreatectomy. Two siblings with a novel dominant mutation showed good response to medical treatment. Although the HH remitted in early infancy, they became diabetic at the prepubertal age. Their mother, maternal aunt and maternal grandfather had the same mutation without any medical history of neonatal HH. CONCLUSION: The clinical presentation of our two patients with a dominant ABCC8 mutation was milder than that of patients with the resessive form of the disease as they responded well to medical management.

Transient neonatal diabetes with two novel mutations in the KCNJ11 gene and response to sulfonylurea treatment in a preterm infant.

Neonatal diabetes mellitus (NDM) is a rare condition that can be either transient or permanent. K(ATP) channel (Kir6.2 or SUR1) mutation, chromosome 6 abnormalities, insulin, or glucokinase gene mutations can lead to isolated NDM. Cases caused by Kir6.2 mutation usually result in permanent NDM (PNDM) rather than transient NDM (TNDM). The majority of patients with the Kir6.2 or SUR1 mutation can be successfully managed with a sulfonylurea agent, without the need for insulin. We report a preterm male with NDM having two novel missense mutations, E322A and D352H, in the KCNJ11 gene. At 2 months of age, successful transition from insulin to glibenclamide (glyburide) therapy of the patient was managed. At 5 months of age, his diabetes went in to remission.

A novel mutation of 5alpha-steroid reductase 2 deficiency (CD 65 ALA-PRO) with severe virilization defect in a Turkish family and difficulty in gender assignment.

Molecular genetic characterization of mutations in SRD5A2 gene is used as an essential procedure for the final diagnosis of 5alpha-reductase deficiency. Here, we report a novel homozygous point mutation of SRD5A2 gene at codon 65 in exon 1, due to a proline for alanine substitution in a Turkish family whose proband has severe undervirilization. This mutation has not been reported up to date in association with 5alpha-reductase deficiency in various ethnic groups. We discussed some questions about gender assignment in addition to the molecular and clinical characteristics of the disease.

The effect of colchicine on physical growth in children with familial mediterranean fever.

Familial Mediterranean fever (FMF) is an autosomal recessive disease, characterized by recurrent, self-limited attacks of fever with serositis involving the peritoneum, pleura, and joints. There is very scarce information on physical growth of affected children. The aim of this study was to determine whether there is significant improvement in growth parameters in FMF patients after colchicine treatment. Patient files were retrospectively evaluated and patients that used colchicine for more than 1 year were included in the study. Demographic features, clinical findings before and after colchicine therapy, duration and dosage of therapy, weight, height, parentally adjusted height, and body mass index before and after colchicine therapy were noted and transformed into standard deviation scores (SDS). The study group consisted of 50 FMF (25 male and 25 female) patients. Median age at the time of diagnosis was 6.5 years. Median follow-up period was 3.6 (1-12.5) years. Mean height SDS increased from -0.19 +/- 1.01 to 0.13 +/- 0.99 (p = 0.026), and mean parentally adjusted height increased from -0.18 +/- 1.23 to 0.13 +/- 1.24 (p = 0.027), and both of them were found to be statistically significant. Mean body mass index SDS increased from -0.61 +/- 1.32 to -0.32 +/- 1.33, but this improvement was statistically insignificant (p = 0.18). In this study, we found that colchicine significantly improved height development in FMF patients.

Amiodarone-induced thyrotoxicosis in children and adolescents is a possible outcome in patients with low iodine intake.

BACKGROUND/OBJECTIVE: The identification of the different subtypes of amiodarone-induced thyrotoxicosis (AIT) may provide a rational basis for the choice of the appropriate medical treatment. The aim of this study was to evaluate differential diagnosis and treatment regimens of AIT in children and adolescent. PATIENTS: We reported 3 patients: A 6.7 years old boy with type I AIT; a 17.9 years old girl with type II AIT and a 14.6 years old girl with mixed type AIT. CONCLUSIONS: AIT is not an uncommon complication in countries with low iodine intake. AIT can be asymptomatic and can occur at any time in patients receiving amiodarone therapy. It is also very important to distinguish the type of AIT when planning therapy. Steroid therapy should be started when findings indicate type II or mixed-type AIT. Beta blockers may prevent heart thyrotoxicosis and recurrence of primary arrhythmia if amiodarone is discontinued.

Effect of interferon therapy on glucose metabolism in children with chronic hepatitis B.

The aim of this study was to investigate the effect of interferon (IFN)-alpha treatment on glucose metabolism in children with chronic hepatitis B (CHB). Forty children with CHB received IFN 10 MU/m2 for six months. Oral glucose tolerance test, anti-insulin and anti-glutamic acid decarboxylase (GAD) antibody, fasting plasma C-peptide and insulin (FPI), postprandial insulin, homeostasis model assessment of insulin resistance (HOMA-IR), HOMA-cell, and glucose/insulin ratio (G/I) were measured before and after treatment. The last four parameters were also evaluated in healthy controls (n=42). In patients, fasting plasma glucose (FPG) and HOMA-IR levels were significantly lower than in controls (p = 0.001 and p = 0.020, respectively). There was a strong correlation between degree of liver disease and FPG. Two patients had hyperinsulinemia. HOMA-IR was suppressed in 7 patients enough to indicate increased sensitivity. FPI of 13 patients and HOMA-cell of 9 patients were lower than the minimum level of controls, features compatible with beta-cell hypofunction. Frequency of glucose metabolism abnormalities was not different before and after therapy. After therapy, only 1 patient developed anti-GAD antibody, and FPI of 8 children and HOMA-cell level of 9 children were lower than the minimum level of controls. Hyperinsulinemia was persistent in the same patients. We demonstrated that HBV-infected children had insulin sensitivity; however, no adverse effects of IFN on glucose homeostasis were seen.

Final height of patients with classical congenital adrenal hyperplasia.

The management of children with congenital adrenal hyperplasia (CAH) remains a challenge, especially with regard to their growth potential. We aimed to determine the correlation of the final height of Turkish children with classical CAH to their genetic height potential and to determine the effect of hydrocortisone replacement therapy on the final height. A total of 24 CAH (16 simple virilizing and 8 salt-wasting form) were included in this retrospective longitudinal study. The final height (FH), final height standard deviation score (FHSDS), target height (TH), target height standard deviation score (THSDS), corrected height for target height (CHSDS), weight, and body mass index (BMI) were calculated for all patients. We evaluated the adult height taking into consideration the correlation with the genetic height potential and the country standards. The average follow-up time was 14.2 +/- 3.1 years and the average daily hydrocortisone dose was 19.7 +/- 2.9 mg/m2. The mean FH and FHSDS were 152.2 +/- 7.2 cm and -1.0 +/- 1.1 SD, respectively, in females and 163.1 +/- 6.6 cm and -1.2 +/- 1.0 SD, respectively, in males. The CHSDS was found to be -0.73 +/- 0.9 SD. FH was below the TH in 79.1% of our cases. In 20.8% of our patients, FH was less than the third percentile for the standard height for our country. Interestingly, the FH showed no correlation with the dosage of hydrocortisone. Thirteen of our cases (54.2%) reaching FH were obese/overweight. A positive correlation was detected between hydrocortisone treatment and the BMI. The observations that 79.1% of our classical CAH cases receiving an average daily hydrocortisone dose of 19.7 +/- 2.9 mg/m2 ended up with an adult height below the TH and that 54.2% of the cases were overweight/obese lead us to believe that we should be using the lowest possible dose for treatment.

Persistently raised thyroid stimulating hormone in adequately treated congenital hypothyroidism on long-term follow-up.

AIM: To determine the percentage of patients with inappropriate secretion of TSH (ISTSH) in a large cohort of patients with congenital hypothyroidism (CH), and to examine a probable influence of the pretreatment T4 or TSH levels and the etiology of CH on ISTSH by describing the clinical features of these patients. PATIENTS AND METHODS: We retrospectively examined the records, including anthropometric data, clinical findings, and thyroid function tests (TFT), of 500 children diagnosed with CH. Inclusion criteria of ISTSH were appropriate doses of L-T4, improvement of clinical findings, normalization of serum total T4 levels and persistently high TSH concentrations. A group of patients who demonstrated adequate suppression of TSH (<6 mU/l) with therapy among 500 CH patients were chosen randomly as a control group. Both groups were compared with regard to the etiology of CH, and TFT at baseline and during the treatment period. RESULTS: Overall, 27 (5.4%) out of the 500 patients with CH had ISTSH. Nine patients (1.8%) with ISTHS did not show TSH normalization during the follow-up period. Four out of 27 patients with ISTSH had organic lesions (three empty sella, one corpus callosum agenesis) on cranial imaging. No statistically significant difference was found between the groups for etiological classification. The pretreatment T4 and TSH levels in ISTHS and control groups were not significantly different. CONCLUSIONS: Our results suggest that a minority (5.4%) of adequately treated children with CH have persistently raised TSH levels. The delay in normalization of TSH is not related to pretreatment T4 and TSH values or the etiology of CH.

Paternal X could relate to arithmetic function; study of cognitive function and parental origin of X chromosome in Turner syndrome.

BACKGROUND: 45,X Turner syndrome (TS) female subjects have visuospatial skill and social cognition deficits that may arise from X-linked imprinting. The aim of the present study was to compare phenotypic characteristics and neurocognitive pattern of 12 monosomic TS girls, according to X-linked imprinting. METHODS: Microsatellite markers were used to determine the parental origin of the missing chromosome X. Wechsler Intelligence Scale for Children-Revised (WISC-R) was administered as measures of general intellectual functioning. The results were compared in TS patients with maternally derived X chromosome (Xm) and paternally derived X chromosome (Xp). RESULTS: Six out of 12 patients (50%) had Xm, and the other six (50%) had Xp chromosome. There was no difference in the total, verbal and performance IQ score between the TS subgroups with Xm and Xp. When the WISC-R subtest score patterns were compared, the mean arithmetic scores were significantly poorer in the Xm TS than in the Xp TS. CONCLUSION: In monosomic TS cases, paternal imprinting may predict arithmetic ability, on the other hand, reductionist consideration defined by genetic imprinting is not sufficient to confirm this. Further studies should be undertaken to clarify this situation.

Evaluation of glucose homeostasis in transfusion-dependent thalassemic patients.

Diabetes is an important problem encountered in thalassemic patients. The severity and type of glucose disturbances vary greatly in different studies. Also the pathogenesis seems to be complex; either insulin deficiency or insulin resistance may mediate the glucose disturbances. In a group of thalassemic patients glucose homeostasis was evaluated. Diabetes prevalence was 1.8%. Forty patients were investigated both with an oral glucose tolerance test and first-phase insulin response. Three patients had impaired fasting glucose, 1 patient had impaired glucose tolerance, and 2 patients had hyperinsulinism. Nineteen of 40 patients who were tested had low first-phase insulin response (47.5%) with below 10th centile. Age, BMI, height SDS, age at diagnosis, age at first blood transfusion, number of blood transfusions in a year, percentage of elevated liver enzyme, and hemoglobin and ferritin levels were not different between patients with low first-phase insulin response to patients with normal first-phase insulin response. Four patients are HCV infected, and only 1 of them had low first-phase insulin response. The study group showed a high rate of impairement in insulin secretion by first-phase insulin response to glucose overload, despite the low rate of insulin resistance. Defect of insulin secretion in thalassemic patients may develop earlier than insulin resistance, and then be accompanied by insulin resistance. Increasing insulin resistance with age and the occurrence of additional factors could lead to detoriation of glucose metabolism.

The incidence and evolution of thyroid dysfunction during interferon-alpha therapy in children with chronic hepatitis B infection.

AIM: To assess the effect of interferon-alpha (IFN-alpha) therapy on thyroid functions in children with chronic hepatitis B infection (CHB). METHODS: Sixty-eight children (7.8 +/- 3.6 years) were treated with 5 (n = 37, group I) or 10 MU/m2 (n = 31, group II) IFN for 6 months. Thyroid hormones, thyrotropin, thyrotropin-releasing hormone stimulation test, thyroid peroxidase and thyroglobulin autoantibodies were evaluated. RESULTS: Baseline features were not different in the two groups. After therapy, thyroid dysfunction was 27% and 41.9% in groups I and II (n.s.). Subclinical hypothyroidism was 17.9%/ 29%, subclinical hyperthyroidism 5.4%/12.9%, hypothyroidism 2.7%/-, and thyroid antibody positivity 2.7%/- in groups I and II (n.s.). Thyroid dysfunction was 33.8% in the whole group (p = 0.001). Predictors of IFN induced-thyroid dysfunction were female sex and age < 6 years. Thyroid dysfunction resolved within median 6 months in all but three children. CONCLUSION: Although IFN-induced thyroid dysfunction is mostly subclinical and reversible, this side effect should be kept in mind.