Ali Kemal Topaloglu

Twenty novel mutations in the alpha-galactosidase A gene causing Fabry disease.

BackgroundFabry disease, an X-linked inborn error of glycosphingolipid catabolism, results from the deficient activity of the lysosomal exoglycohydrolase α-galactosidase A (EC 3.2.1.22; α-Gal A). The nature of the molecular lesions in the α-Gal A gene in 30 unrelated families was determined to provide precise heterozygote detection, prenatal diagnosis, and define genotype-phenotype correlations.Materials and MethodsGenomic DNA was isolated from affected males and/or carrier females from 30 unrelated families with Fabry disease. The entire α-Gal A coding region and flanking intronic sequences were analyzed by PCR amplification and automated sequencing.ResultsTwenty new mutations were identified, each in a single family: C142R, G183D, S235C, W236L, D244H, P259L, M267I, I289F, Q321E, C378Y, C52X, W277X, IVS4+4, IVS6+2, IVS6−1, 35del13, 256del1, 892ins1, 1176del4, and 1188del1. In the remaining 10 unrelated Fabry families, 9 previously reported mutations were detected: M42V, R112C, S148R, D165V, N215S (in 2 families), Q99X, C142X, R227X, and 1072del3. Haplotype analysis using markers closely flanking the α-Gal A gene indicated that the two patients with the N215S lesion were unrelated. The IVS4+4 mutation was a rare intronic splice site mutation that causes Fabry disease.ConclusionsThese studies further define the heterogeneity of mutations in the α-Gal A gene causing Fabry disease, permit precise heterozygote detection and prenatal diagnosis, and help delineate phenotype-genotype correlations in this disease.

The effects of neurokinin B upon gonadotrophin release in male rodents.

Growing evidence suggests the tachykinin neurokinin B (NKB) may modulate gonadotrophin secretion and play a role in sex‐steroid feedback within the reproductive axis. NKB signalling has recently been identified as being necessary for normal human reproductive function, although the precise mechanisms underpinning this role remain to be established. We have used rodents to explore further the role of NKB within the reproductive axis. In particular, we have studied its interactions with kisspeptin, a neuropeptide essential for reproductive function in rodent and human with close anatomical links to NKB within the hypothalamus. Intraperitoneal administration of NKB (50 nmol) to male mice had no effect on circulating luteinsing hormone (LH) levels and, although i.p. kisspeptin (15 nmol) increased LH five‐fold, co‐administration of NKB and kisspeptin was indistinguishable from kisspeptin alone. Intracerebroventricular administration of NKB (10 nmol) to male mice also had no effect on LH levels, with 1 nmol kisspeptin i.c.v. significantly increasing LH compared to control (0.37 ± 0.18 versus 5.11 ± 0.28 ng/ml, respectively). Interestingly, i.c.v. co‐administration of NKB and kisspeptin caused a significant increase in LH concentrations compared to kisspeptin alone (8.96 ± 1.82 versus 5.11 ± 0.28 ng/ml respectively). We used hypothalamic explants from rats to assess the effect of NKB on gonadotrpohin‐releasing hormone (GnRH) secretion ex vivo. Doses of NKB up to 1000 nm failed to stimulate GnRH secretion, whereas 100 nm kisspeptin robustly increased GnRH secretion. Of note, co‐administration of NKB with kisspeptin abrogated the effect of kisspeptin, producing no GnRH release above basal state. Finally, we analysed the expression of Tac2/Tacr3 (genes encoding NKB and NK3R, respectively) within the arcuate nucleus in different nutritional states. After a 48‐h fast, the expression of both Tac2 and Tacr3 showed a significant increase, in contrast to levels of Kiss1 and Kiss1r mRNA, which remained unchanged. In male rodent models, NKB and kisspeptin have different effects upon gonadotrophin release and appear to interact in a complex manner.

Thyroid hormone levels and their relationship to survival in children with bacterial sepsis and septic shock.

Objectives: Reported studies have showed alternations of thyroid hormones in critical illness mostly in adults and some in children. In this study, we aimed to measure thyroid hormone levels in children with sepsis and septic shock and investigate the relationship of these hormones with clinical state and survival. Patients and Methods: Thyroid hormone levels of children with sepsis and septic shock, and age-and sex-matched controls were measured. Results: There were 51 children in sepsis (group S), 21 children in septic shock (group SS) and 30 in the control (group C) group. Total triiodothyronine (TT 3 ) levels were (nmol/l): 0.91 ′ 0.22, 0.64 ′ 0.23, 2.11 ′ 0.59; free triiodothyronine (FT 3 ) (pmol/l): 0.027 ′ 0.006, 0.018 ′ 0.007, 0.049 ′ 0.010; total thyroxine (TT 4 ) (nmol/l): 100.62 ′ 21.93, 65.79 ′ 19.35, 109.65 ′ 19.35; free thyroxine (FT 4 ) (pmol/l): 18.06 ′ 3.87, 10.32 ′ 1.29, 19.35 ′ 3.87; and thyroid stimulating hormone (TSH) (mIU/ml): 5.0 ′ 2.0, 4.8 ′ 2.4, 5.2 ′ 3.0, in children with sepsis, septic shock, and controls, respectively. The TT 3 , FT 3 , TT 4 , and FT 4 levels of group SS were significantly lower than those of groups S and C. The TT 3 and FT 3 levels of group S were lower than in group C, but there was no significant difference between TT 4 , and FT 4 levels of groups S and C. TSH levels were slightly decreased in both sepsis and septic shock, but the difference was not significant. Eleven (21.6%) children with sepsis and 15 (71.4%) children with septic shock died (p <0.001). The levels of TT 3 , FT 3 , TT 4 and FT 4 were markedly lower in non-survivors of groups S and SS compared to survivors (p <0.001). Conclusions: These changes in the hypothalamopituitary-thyroidal axis may suggest a possible prognostic value of thyroid hormone levels in children with sepsis and septic shock. To the best of our knowledge, this report is the first study to compare thyroid hormone levels in a large number of patients with sepsis and septic shock with those in healthy controls in childhood.

Growth hormone and insulin‐like growth factor 1 levels and their relation to survival in children with bacterial sepsis and septic shock

Objectives:  Despite improved supportive care, the mortality of sepsis and septic shock is still high. Multiple changes in the neuroendocrine systems, at least in part, are responsible for the high morbidity and mortality. A reduced circulating level of insulin‐like growth factor and an elevated level of growth hormone are the reported characteristic findings early in the course of sepsis and septic shock in adults. The aim of this study was to evaluate the changes of growth hormone/insulin‐like growth factor 1 axis in sepsis and septic shock and investigate the relationship between these hormones and survival.

Serum IL-1, IL-2, TNFα and INFγ levels of patients with type 1 diabetes mellitus and their siblings

: Type 1 diabetes mellitus (DM) develops as a result of autoimmune destruction of the pancreatic beta-cells. The aim of this study was to explore possible associations between serum levels of cytokines, IL-1, IL-2, TNFalpha and INFgamma and metabolic parameters in children with type 1 DM and their non-diabetic siblings to determine whether these cytokines could be indicators of disordered immune regulation. The study population consisted of 41 children with type 1 DM, 32 non-diabetic siblings, and 28 healthy controls. Children with DM were divided into three subgroups: 1) newly diagnosed patients with diabetic ketoacidosis (ND + DKA), 2) newly diagnosed patients without DKA (ND - DKA), and 3) previously diagnosed patients (PD). The highest serum IL-1alpha level was found in the ND - DKA group, which was significant compared to both the ND + DKA (p < 0.05) and the siblings (S) (p < 0.005). IL-2 levels were similar among all groups. The highest TNFalpha level was observed in the ND + DKA group, which was significant against the ND - DKA (p < 0.05), PD (p < 0.001), S (p < 0.05), and control (C) (p < 0.005) groups. TNFalpha concentration in the PD group was significantly lower than those of S (p< 0.005) and C (p < 0.001) groups. The ND - DKA group had the highest INFgamma and this was statistically significant when compared with the S (p < 0.005) and C (p < 0.05) groups. Both the newly diabetics and all diabetics as a group had statistically significantly higher INFgamma levels than both the S (p < 0.01 for both) and C (p < 0.05 for both) groups. In the diabetics as a whole group, TNFalpha showed correlations with INFgamma (r = 0.370, p < 0.05). IL-1 showed correlation with TNFalpha (r = 0.368, p < 0.05) INFgamma (r = 0.796, p < 0.001) and IL-2 (r = 0.862, p < 0.001) in the all diabetics group. IL-2 was correlated with TNFalpha (r = 0.320, p < 0.05) and INFgamma (r = 0.754, p < 0.01) in the all diabetics group. In conclusion, our results suggest that proinflammatory cytokines TNFalpha, INFgamma, IL-1alpha and IL-2 may play important roles alone or in combination in the pathogenesis of type 1 diabetes mellitus.

Denver developmental screening test II for early identification of the infants who will develop major neurological deficit as a sequalea of hypoxic-ischemic encephalopathy.

Abstract Background : The primary aim of this study was to find widely available, inexpensive, and non‐invasive parameters for early identification or prediction of the infants with hypoxic‐ischemic encephalopathy (HIE) who will have a severe adverse outcome (classified as death or a major neurological deficit).

Evaluation of Cerebral Maturation by Visual and Quantitative Analysis of Resting Electroencephalography in Children With Primary Nocturnal Enuresis

This study was undertaken to evaluate resting electroencephalographic (EEG) changes and their relations to cerebral maturation in children with primary nocturnal enuresis. Cerebral maturation is known to be important in the pathogenesis of this disorder. Twenty-five right-handed patients with primary nocturnal enuresis, aged 6 to 14 years, and 23 age- and sex-matched healthy children were included in this cross-sectional case-control study. The abnormalities detected using such techniques as hemispheral asymmetry, regional differences, and hyperventilation response in addition to visual and quantitative EEG analysis were examined statistically by multivariate analysis. A decrease in alpha activity in the left (dominant hemisphere) temporal lobe and in the frontal lobes bilaterally and an increase in delta activity in the right temporal region were observed. We concluded that insufficient cerebral maturation is an important factor in the pathogenesis of primary nocturnal enuresis, and EEG, as a noninvasive and inexpensive method, could be used in evaluating cerebral maturation. (J Child Neurol 2001;16:714-718).

Distribution of gene mutations associated with familial normosmic idiopathic hypogonadotropic hypogonadism.

Objective: Normosmic idiopathic hypogonadotropic hypogonadism (nIHH) is characterized by failure of initiation or maintenance of puberty due to insufficient gonadotropin release, which is not associated with anosmia/hyposmia. The objective of this study was to determine the distribution of causative mutations in a hereditary form of nIHH. Methods: In this prospective collaborative study, 22 families with more than one affected individual (i.e. multiplex families) with nIHH were recruited and screened for genes known or suspected to be strong candidates for nIHH. Results: Mutations were identified in five genes (GNRHR, TACR3, TAC3, KISS1R, and KISS1) in 77% of families with autosomal recessively inherited nIHH. GNRHR and TACR3 mutations were the most common two causative mutations occurring with about equal frequency. Conclusions: Mutations in these five genes account for about three quarters of the causative mutations in nIHH families with more than one affected individual. This frequency is significantly greater than the previously reported rates in all inclusive (familial plus sporadic) cohorts. GNRHR and TACR3 should be the first two genes to be screened for diagnostic purposes. Identification of causative mutations in the remaining families will shed light on the regulation of puberty. Conflict of interest:None declared.

Molecular causes of hypogonadotropic hypogonadism.

Purpose of review What controls puberty remains largely unknown and current gene mutations account for only about one-third of the apparently genetic cases of idiopathic hypogonadotropic hypogonadism. Lately important developments have occurred in this field. Recent findings Substantial variation in clinical expression, from complete anosmia and hypogonadotropic hypogonadism to delayed puberty and normosmia, of the same Kallmann syndrome gene defects including in newer ones (FGF8 and CHD7) continues to be repeatedly observed. Digenic or oligogenic inheritance becomes another feature of Kallmann syndrome. Recent reports of mutations in TAC3 or TACR3 [encoding neurokinin B (NKB) and its receptor, NK3R, respectively] provided compelling evidence for the involvement of NKB signaling in puberty. This energized the field to understand the exact mechanism through which NKB signaling exerts its effects. With the important findings from these recent studies in association with the substantial data from kisspeptin studies in the last 6 years a sketch of GnRH pulse generator has emerged in which NKB signaling appears to play a key role. Summary Autozygosity mapping may continue helping identify the other genes including those upstream to the GnRH pulse generator in this complex and elusive developmental process.

A homozygous recurring mutation in WISP3 causing progressive pseudorheumatoid arthropathy.

Abstract WISP3 is a member of the CCN (for CTGF, CYR61, and NOV) gene family, which encodes cysteine-rich secreted proteins with roles in cell growth and differentiation. Mutations in the WISP3 gene are associated with the autosomal recessive skeletal disorder, also known as progressive pseudorheumatoid arthropathy of childhood (PPAC). We diagnosed three siblings from a non-consanguineous family with PPAC. The patients were asymptomatic in early childhood. Signs and symptoms of disease that include progressive joint stiffness, swelling of the finger joints, and osteopenia, and slow linear growth developed between 2 and 8 years of age. PCR amplification and direct sequencing of the WISP3 gene revealed a homozygous mutation at nucleotide 156 of the WISP3 gene, resulting in a Cys52-to-ter substitution. This mutation has previously been reported in French, Italian, and Arab families. Interestingly, the C52X mutation was found to be associated with a c.248G→A (G83E) variation, suggesting the existence of a founder effect. By contrast, the presence of the same aberration in three different ethnic groups could imply that this particular site is prone to mutation. Basal fasting concentrations of growth hormone, insulin-like growth factor-1, and insulin-like growth factor binding protein-3, as well as glucose and insulin levels revealed no aberrations. In conclusion, consideration of this rare disease that causes significant morbidity with short stature, osteopenia and arthritic complaints would prevent unnecessary examinations and treatment attempts. Testing for this specific mutation in suspected cases could provide a rapid and definitive diagnosis.