Enver Simsek

A new mutation of the fukutin gene in a non‐Japanese patient

Fukuyama‐type congenital muscular dystrophy (FCMD), Walker–Warburg syndrome, and muscle‐eye‐brain disease are clinically similar autosomal recessive disorders characterized by congenital muscular dystrophy, cobblestone lissencephaly, and eye anomalies. FCMD is frequent in Japan, but no FCMD patient with confirmed fukutin gene mutations has been identified in a non‐Japanese population. Here, we describe a Turkish CMD patient with severe brain and eye anomalies. Sequence analysis of the patients DNA identified a homozygous 1bp insertion mutation in exon 5 of the fukutin gene. To our knowledge, this is the first case worldwide in which a fukutin mutation has been found outside the Japanese population. This report emphasizes the importance of considering fukutin mutations for diagnostic purposes outside of Japan. Ann Neurol 2003

Sonographic Assessment of the Normal Limits and Percentile Curves of Liver, Spleen, and Kidney Dimensions in Healthy School-Aged Children

The purpose of this study was to determine the normal standards of liver, spleen, and kidney dimensions and the relationship of each with sex, age, body weight, height, body mass index, and body surface area in healthy school‐aged children.

Genome-Wide Homozygosity Analysis Reveals HADH Mutations as a Common Cause of Diazoxide-Responsive Hyperinsulinemic-Hypoglycemia in Consanguineous Pedigrees

HADH mutations are common in consanguineous pedigrees with diazoxide-responsive hyperinsulinaemichypoglycemia; therefore, genetic testing is recommended, even in the absence of abnormal fatty acid oxidation.

Natural History of Congenital Generalized Lipodystrophy: A Nationwide Study From Turkey

CONTEXT Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by near-total lack of body fat. OBJECTIVE We aimed to study natural history and disease burden of various subtypes of CGL. DESIGN We attempted to ascertain nearly all patients with CGL in Turkey. SETTING This was a nationwide study. PATIENTS OR OTHER PARTICIPANTS Participants included 33 patients (22 families) with CGL and 30 healthy controls. MAIN OUTCOME MEASURE(S) We wanted to ascertain genotypes by sequencing of the known genes. Whole-body magnetic resonance imaging was used to investigate the extent of fat loss. Metabolic abnormalities and end-organ complications were measured on prospective follow-up. RESULTS Analysis of the AGPAT2 gene revealed four previously reported and four novel mutations (CGL1; c.144C>A, c.667_705delinsCTGCG, c.268delC, and c.316+1G>T). Analysis of the BSCL2 gene revealed four different homozygous and one compound heterozygous possible disease-causing mutations (CGL2), including four novel mutations (c.280C>T, c.631delG, c.62A>T, and c.465-468delGACT). Two homozygous PTRF mutations (c.481-482insGTGA and c.259C>T) were identified (CGL4). Patients with CGL1 had preservation of adipose tissue in the palms, soles, scalp, and orbital region, and had relatively lower serum adiponectin levels as compared to CGL2 patients. CGL4 patients had myopathy and other distinct clinical features. All patients developed various metabolic abnormalities associated with insulin resistance. Hepatic involvement was more severe in CGL2. End-organ complications were observed at young ages. Two patients died at age 62 years from cardiovascular events. CONCLUSIONS CGL patients from Turkey had both previously reported and novel mutations of the AGPAT2, BSCL2, and PTRF genes. Our study highlights the early onset of severe metabolic abnormalities and increased risk of end-organ complications in patients with CGL.

Leucine-sensitive hyperinsulinaemic hypoglycaemia in patients with loss of function mutations in 3-Hydroxyacyl-CoA Dehydrogenase

BackgroundLoss of function mutations in 3-Hydroxyacyl-CoA Dehydrogenase (HADH) cause protein sensitive hyperinsulinaemic hypoglycaemia (HH). HADH encodes short chain 3-hydroxacyl-CoA dehydrogenase, an enzyme that catalyses the penultimate reaction in mitochondrial β-oxidation of fatty acids. Mutations in GLUD1 encoding glutamate dehydrogenase, also cause protein sensitive HH (due to leucine sensitivity). Reports suggest a protein-protein interaction between HADH and GDH. This study was undertaken in order to understand the mechanism of protein sensitivity in patients with HADH mutations.MethodsAn oral leucine tolerance test was conducted in controls and nine patients with HADH mutations. Basal GDH activity and the effect of GTP were determined in lymphoblast homogenates from 4 patients and 3 controls. Immunoprecipitation was conducted in patient and control lymphoblasts to investigate protein interactions.ResultsPatients demonstrated severe HH (glucose range 1.7–3.2 mmol/l; insulin range 4.8-63.8 mU/l) in response to the oral leucine load, this HH was not observed in control patients subjected to the same leucine load. Basal GDH activity and half maximal inhibitory concentration of GTP was similar in patients and controls. HADH protein could be co-immunoprecipitated with GDH protein in control samples but not in patient samples.ConclusionsWe conclude that GDH and HADH have a direct protein-protein interaction, which is lost in patients with HADH mutations causing leucine induced HH. This is not associated with loss of inhibitory effect of GTP on GDH (as in patients with GLUD1 mutations).

Sensitivity of iodine deficiency indicators and iodine status in Turkey.

BACKGROUND Iodine deficiency is a major health problem worldwide. Goiter prevalence and the median urinary iodine concentration in a population usually define endemic iodine deficiency. In addition to goiter prevalence and median urinary concentration, thyroid stimulating hormone (TSH) and thyroxine have been used as iodine deficiency indicators. OBJECTIVE To evaluate endemic goiter prevalence in Western Anatolia, Turkey, and to evaluate the sensitivity of thyroglobulin and height percentile as iodine deficiency indicators. SUBJECTS We examined 727 school-children (378 girls, 349 boys) in two cities (Bolu and Düzce) and six mountainous rural areas, in West Anatolia. Of the 727 children, 234 were from four urban schools, and 493 were from eight rural schools. METHODS Clinical examination and ultrasonography were used to evaluate goiter prevalence. Iodine in spot urine, serum total thyroxine (T4), serum free thyroxine (FT4), thyroid stimulating hormone (TSH), and thyroglobulin (Tg) were measured. Iodine deficiency severity was classified based on thyroid volume measurements by ultrasonography and urinary iodine excretion. RESULTS The degree of iodine deficiency according to concentration of urinary iodine was severe in 276 children (38%), moderate in 151 (20.8%), mild in 114 (15.7%), and within normal levels in 186 (25.4%). Although urban areas showed normal or mild urinary iodine excretion, four rural areas showed from mild to severe iodine deficiency (p < 0.001). Thyroid volumes of the severe iodine deficiency group were significantly higher than those of moderate and mild iodine deficiency groups (p < 0.001). There was no significant difference between thyroid volumes in moderate and mild iodine deficiency groups. FT4 levels of the severe iodine deficiency group were significantly lower than in moderate and mild iodine deficiency groups (p < 0.001). There was no significant correlation between TSH and iodine excretion (r = 0.01, p > 0.05). Thyroglobulin (Tg) levels were significantly different between all groups (p < 0.001). There was a significant negative correlation between Tg and urinary iodine excretion (r = -0.27, p < 0.001). CONCLUSIONS Severe and moderate iodine deficiency areas are more prevalent in Turkey than mild and normal iodine concentration areas. In addition to urinary iodine concentration and thyroid volume, height percentile and Tg are also sensitive markers for endemic iodine deficiency. TSH screening should be performed nationwide in Turkey. We recommend compulsory iodination of table and industrial salt.

Utility of ApoB/ApoA1 Ratio for the Prediction of Cardiovascular Risk in Children with Metabolic Syndrome

ObjectiveTo assess whether apoB/apoA1 ratio is associated or not with metabolic syndrome in obese children.MethodsA 198 obese children and 41 healthy control subjects were enrolled in a cross-sectional study. The apoB/apoA1 ratio and other metabolic sydrome components in obese children with/without metabolic syndrome were compared to healthy controls.ResultsThe apoA1 level did not show significant difference (p = 0.664) but apoB level (p = 0.000) and apoB/apoA1 ratio (p = 0.001) were significantly higher in obese group than in control group. Also, the apoB/apoA1 ratio was significantly higher in obese children with metabolic syndrome when compared to obese children without metabolic syndrome (p = 0.007) and showed positive correlation with triglyceride (r = 0.404, p = 0.000) and negative correlation with high-density lipoprotein cholesterol (r = −0.593, p = 0.000).ConclusionsThe apoB/apoA1 ratio is associated with metabolic syndrome in obese children. An elevated apoB/apoA1 ratio may constitute an important feature of the metabolic syndrome. There is a need for long term follow-up studies concerning cardiovascular risk in obese children with metabolic syndrome and high apoB/apoA1 ratio.

Prevalence of nonclassic congenital adrenal hyperplasia in Turkish children presenting with premature pubarche, hirsutism, or oligomenorrhoea.

Background. Nonclassic congenital adrenal hyperplasia (NCAH), caused by mutations in the gene encoding 21-hydroxylase, is a common autosomal recessive disorder. In the present work, our aim was to determine the prevalence of NCAH presenting as premature pubarche (PP), hirsutism, or polycystic ovarian syndrome (PCOS) and to evaluate the molecular spectrum of CYP21A2 mutations in NCAH patients. Methods. A total of 126 patients (122 females, 4 males) with PP, hirsutism, or PCOS were included in the present study. All patients underwent an ACTH stimulation test. NCAH was considered to be present when the stimulated 17-hydroxyprogesterone plasma level was >10 ng/mL. Results. Seventy-one of the 126 patients (56%) presented with PP, 29 (23%) with PCOS, and 26 (21%) with hirsutism. Six patients (4,7%) were diagnosed with NCAH based on mutational analysis. Four different mutations (Q318X, P30L, V281L, and P453S) were found in six NCAH patients. One patient with NCAH was a compound heterozygote for this mutation, and five were heterozygous. Conclusion. NCAH should be considered as a differential diagnosis in patients presenting with PP, hirsutism, and PCOS, especially in countries in which consanguineous marriages are prevalent.

Two Frameshift Mutations in MKRN3 in Turkish Patients with Familial Central Precocious Puberty.

Background: Little is known about the genetic causes responsible for idiopathic central precocious puberty (iCPP). More recently, described loss-of-function mutations in the makorin ring finger protein 3 (MKRN3) gene have been demonstrated to be involved in the pathogenesis of familial iCPP. Aim: The objective of this study was to investigate the potential role of MKRN3 in patients with familial iCPP. Methods: We investigated potential sequence variations in the maternal imprinted MKRN3 gene using Next Generation Sequencing (NGS) analysis in 31 participants from 2 families (6 participants were diagnosed with familial iCPP on the basis of clinical and hormonal findings). Six patients diagnosed with familial iCPP and their unaffected first- and second-degree relatives, including their grandparents, were screened for MKRN3 gene variants. Results: Two heterozygous frameshift mutations (c.441_441delG, p.H148Tfs*23 and c803_803delAT, p.M268Vfs*23) were described in the MKRN3 gene in 2 probands with familial iCPP and in some of their family members. These frameshift mutations create a premature stop codon and result in a truncated protein. Conclusions: Our report further expands the MKRN3 gene mutation spectrum in patients with familial iCPP. Screening for potential MKRN3 variants should be performed in patients with familial iCPP as well as in patients with sporadic iCPP.

Growth hormone and the risk of atherosclerosis in growth hormone-deficient children.

OBJECTIVE Growth hormone-deficient (GHD) children have been found to have higher cardiovascular mortality rates and an increased carotid intima-media thickness (CIMT). This study investigated the risk of atherosclerosis and the effect of recombinant growth hormone (rhGH) replacement therapy on the lipid profile and CIMT in GHD children. DESIGN A total of 40 GHD children (mean age: 12.3±2.04 years) were investigated before and after 1 year of rhGH therapy at a dosage of 0.03 mg/kg/day and 40 age- and sex-matched healthy children (mean age: 12.1±2.23 years) were enrolled as a control group, in the same pubertal stage. Fasting blood samples were obtained for lipid profile, IGF-1, and IGFBP-3 analyses. The patients and controls underwent CIMT measurements before and after 1 year of rhGH treatment. RESULTS The growth velocity and height standard deviation scores increased significantly over 1 year of treatment in all patients. The total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and atherogenic index (Ai) values were increased while the high-density lipoprotein (HDL) cholesterol value was decreased in the GHD children, as compared to the controls; however, the triglyceride (TG) level was comparable. After 1 year of treatment, a significant decrease in the TC, LDL cholesterol, and Ai values as well as a significant increase in the HDL value were observed in the GHD patients, with the values becoming similar to those in the control group. The mean CIMT was significantly greater in the GHD subjects than in the controls. After 1 year of therapy, the CIMT in the GHD subjects had decreased significantly; however, it was still greater than that in the control group. IGF-1 was negatively correlated with TC, LDL cholesterol, Ai, right CIMT, and left CIMT. CONCLUSIONS GHD is associated with increased atherosclerotic risk in children. An improved lipid profile and CIMT were detected after 1 year of hormone replacement therapy.