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Enver Simsek

Publications and source records attributed to Enver Simsek.

9 recordsLinked to original sources
PubMed2006

A novel thyroid hormone receptor-beta mutation that fails to bind nuclear receptor corepressor in a patient as an apparent cause of severe, predominantly pituitary resistance to thyroid hormone.

CONTEXT: Resistance to thyroid hormone (RTH) is a dominantly inherited syndrome of variable tissue hyporesponsiveness to thyroid hormone (TH). OBJECTIVE: We report a newborn who presented with severe RTH (Mkar) with serum TSH 1500 mU/liter and free T(3) greater than 50 pm (normal 3.1-9.4) and free T(4) 25.3 pm (normal 12-22). We hypothesized that the RTH was due to reduced ligand binding and/or abnormal interaction with nuclear cofactors. DESIGN: These were prospective in vivo and in vitro studies. SETTING: The study was conducted at a tertiary care university hospital. PATIENTS: Patients included a newborn child and two other subjects with RTH. INTERVENTION: The effect of various TH-lowering agents in the subject with RTH was studied. In vitro studies including EMSA and mammalian two-hybrid assay as well as in vitro transfection studies were conducted. MAIN OUTCOME MEASURES: Sequencing of the TH receptor (TR)beta and in vitro measurements of receptor-cofactor interaction were measured. RESULTS: Sequencing of the TRbeta demonstrated a de novo heterozygous mutation, 1590_1591insT, resulting in a frameshift producing a mutant TRbeta (mutTR)-beta with a 28-amino acid (aa) nonsense sequence and 2-amino acid carboxyl-terminal extension. The Mkar mutation was evaluated in comparison to three other TRbeta frameshift mutations in the carboxyl terminus. EMSA demonstrated that the Mkar mutTRbeta1 had impaired ability to recruit nuclear receptor corepressor but intact association with silencing mediator of retinoid and thyroid receptor (SMRT). CONCLUSION: Our data suggest that alterations in codons 436-453 in helix 11 result in significantly diminished association with nuclear receptor corepressor but not SMRT. This novel mutTRbeta demonstrates nuclear corepressor specificity that results in severe predominantly pituitary RTH due to impaired release of SMRT.

Amino Acid Sequence↗
PubMed2005

Congenital sialoblastoma (embryoma) associated with premature centromere division and high level of alpha-fetoprotein.

Sialoblastoma is a rare, locally aggressive, and potentially malignant perinatal salivary tumor that predominantly affects the parotid glands. To date, 29 cases of sialoblastoma have been reported. We report a further case of sialoblastoma diagnosed at 37 weeks of gestation presenting with novel findings that are the premature centromere division and a high level of alpha-fetoprotein.

Adult↗
PubMed2005

Isolated 17,20-lyase (desmolase) deficiency in a 46,XX female presenting with delayed puberty.

OBJECTIVE: To investigate the cause of hypergonadotropic hypogonadism. DESIGN: Case report and literature review. SETTING: University Departments of Pediatric Endocrinology and Obstetrics and Gynecology. PATIENT(S): A 13.5-year-old girl with absent puberty and growth retardation. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Detailed biochemical, radiological, and molecular analysis, including pelvic ultrasound, basal steroid hormone analysis in serum and aspirated follicle fluid, serum steroid measurement after ACTH (Synachten) and human chorionic gonadotropin (hCG) stimulation, and molecular analysis of CYP17. RESULT(S): This girl with hypergonadotropic hypogonadism (LH 65 U/L, FSH 50 U/L) had a 46,XX karyotype, small uterus and enlarged cystic ovaries, and markedly delayed bone age (9 years). Basal (serum, follicular) and stimulated (serum) steroid hormone levels were consistent with isolated 17,20-lyase deficiency whereas relatively normal P and 17-hydroxyprogesterone concentrations were detected together with very low androstenedione, T, and E(2) levels. CONCLUSION(S): Isolated 17,20-lyase deficiency should be considered in the differential diagnosis of hypergonadotropic hypogonadism in 46,XX females, and follicular fluid steroid analysis is a useful adjuvant test. Failure to detect mutations in CYP17 raises the possibility of a novel association of these phenotypes.

Adolescent↗
PubMed2005

Sonographic assessment of the normal limits and percentile curves of liver, spleen, and kidney dimensions in healthy school-aged children.

OBJECTIVE: 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. METHODS: Seven hundred twelve healthy school-aged children (7-15 years) in 2 neighboring cities, including rural areas and city centers, were evaluated prospectively. Sex, age, weight, height, body mass index, and body surface area were determined for each case. Organ dimensions were measured 3 times, and the mean values were recorded. All measured organs had a normal position, shape, and echo texture. The children were separated into 5 groups according to body weight. RESULTS: There were no significant differences in organ dimensions with respect to sex (P > .05). The mean right kidney length was shorter than the left kidney length, and the difference was significant (P = .009). Body weight showed the best correlation with liver, spleen, and kidney dimensions. The results were also supported by the variance and covariance of the correlation coefficients. CONCLUSIONS: The normal limits of the liver, spleen, and kidneys are important parameters during a sonographic examination. This study revealed that organ dimensions showed the best correlation with body weight. To our knowledge, in clinical practice there are no pediatric organ dimension percentile graphs for interpretation of sonographic examinations. We hope this study contributes to daily practice in radiology clinics.

Adolescent↗
PubMed2003

Atypical meningioma and extensive calvarium defects in neurofibromatosis type 1.

A 9-year-old girl with neurofibromatosis type 1 (NF1) presented with a massive atypical meningioma and calvarial defect. Skull radiographs and cranial CT showed an extensive lytic bone lesion at the vertex. MRI demonstrated a large mass invading the calvarium and sagittal sinus. The histopathological and immunohistochemical diagnosis of the resected mass was atypical meningioma. To our knowledge, this is the first case of NF1 associated with atypical meningioma and massive calvarial defect in a child.

Child↗
PubMed2003

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 patient's 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.

Amino Acid Sequence↗
PubMed2003

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.

Biomarkers↗
PubMedDate not supplied

Traumatic optic nerve avulsion.

A 10-year-old boy presented with optic nerve avulsion associated with ptosis and limitation of elevation and adduction secondary to blunt ocular trauma. At the initial examination the funduscopic view was hazy because of concurrent vitreous hemorrhage. Ultrasonography revealed a posterior ocular wall defect and a hypolucent area in the region of the optic nerve head.

Child↗