Biomedical subjects

Tolunay Baykal

Publications and source records attributed to Tolunay Baykal.

5 recordsLinked to original sources

PubMed2006

Stroke in childhood: experience in Istanbul, Turkey.

Our objective was to characterize the etiologic factors and outcome for stroke in children. We retrospectively reviewed the charts of patients between the ages of 40 days and 94 months (36.5 +/- 23.7 months) with stroke seen at Istanbul Medical Faculty, Department of Pediatrics between January 1995 and December 2003. We found 79 cases of stroke: 57 ischemic and 22 hemorrhagic strokes. Seventeen children had vitamin K deficiency dependent hemorrhage. In 14 children stroke occurred as a complication of cardiac disease, 7 had moyamoya disease, 3 had protein C deficiency, 2 had thalassemia, 2 had hyperhomocysteinemia (methylene tetrahydrofolate reductase gene mutation), 2 were heterozygote for factor V Leiden, 3 had Down's syndrome, 1 was diagnosed with antiphospholipid syndrome, 1 had glycogen storage disease, and in 28 children no underlying cause could be found. Multiple risk factors were found in 4 children. The outcome in all 79 stroke patients was as follows: asymptomatic 60%; symptomatic epilepsy or persistent neurologic deficit 37%; death 3%; and recurrent stroke 5%. Thus, an underlying cause for stroke was identified in 65% of the children in the study group; 40% of the children either died or suffered motor and/or cognitive sequelae.

Child↗

PubMed2006

Corticospinal tract involvement in a patient with 3-HMG coenzyme A lyase deficiency.

3-Hydroxy-3-methylglutaryl coenzyme A lyase deficiency, an inborn error of ketone body synthesis and leucine degradation, is a rare disorder. There are few reports demonstrating clinical and neuroradiologic findings of this condition. This report describes a 3.5-year-old previously healthy male who was admitted with complex partial seizures and was diagnosed as having 3-hydroxy-3-methylglutaryl coenzyme A lyase deficiency. The patient's previous medical history was unremarkable. His development and neurologic examination were normal. Cranial magnetic resonance imaging indicated prominent corticospinal tract and pontine involvement with focal cerebral white matter changes which have not been described in the literature before.

Child, Preschool↗

PubMed2005

Screening for tetrahydrobiopterin deficiencies using dried blood spots on filter paper.

Tetrahydrobiopterin (BH4) deficiency among newborns with hyperphenylalaninemia must be rapidly diagnosed and distinguished from classical phenylketonuria (PKU) to initiate immediately specific treatment and to prevent irreversible neurological damage. The characteristic pattern of urinary pterins makes it possible to differentiate between PKU and BH4 deficiencies, and to identify different variants of BH4 deficiency. However, collection, storage, and shipment of urine samples for pterin analysis is cumbersome. A method for the measurement of different pterins (neopterin, biopterin, and pterin) in blood collected on filter paper was developed as a potential alternative to the screening for BH4 deficiencies in urine and for the monitoring of BH4 pharmacokinetics. Pterins pattern in blood spots was comparable with those in plasma and urine. We thus established reference values for pterins in blood spots in patients with hyperphenylalaninemia and identified new patients with GTP cyclohydrolase I deficiency, 6-pyruvoyl-tetrahydropterin synthase deficiency, and dihydropteridine reductase deficiency using dried blood spots on filter paper.

Biopterins↗

PubMed2005

Biotinidase deficiency: novel mutations and their biochemical and clinical correlates.

Biotinidase deficiency is a defect in the recycling of the vitamin biotin. Biotin supplementation can markedly improve the neurological and cutaneous symptoms of affected children and prevent symptoms in children identified by newborn screening or treated since birth. We have determined thirteen novel mutations in children with the disorder. Two nonsense mutations, eight single missense mutations, three allelic double missense mutations, and two are polymorphisms were identified in the biotinidase gene (BTD). One of the missense mutations, c.734G>A (p. C245Y), is the first to be reported that alters the cysteine in the putative location crucial for ester formation and binding of the biotinyl-moiety in the active site of the enzyme. These mutations add to the growing list of mutations that are helping to delineate structure/function relationships of the enzyme.

Alleles↗

PubMedDate not supplied

Type II hyperprolinemia: a case report.

Hyperprolinemia type II (HP II) is a rare inherited metabolic disease due to the deficiency of pyroline-5-carboxylate dehydrogenase. It is generally believed to be a benign condition although some patients have neurological problems such as refractory convulsions. Here we report a six-year-old girl with HP II who admitted to our hospital with recurrent seizure refractory to multiple antiepileptic drugs. She was the third child of healthy, consanguineous parents. The family history was negative for neurological and renal disorders. On physical examination, she had no facial dysmorphy; the anthropometric measurements, and systemic and neurological examinations were normal. Mental and motor development was appropriate for her age. Laboratory findings revealed elevated levels of proline, glycine, and ornithine in serum and pyrroline-5-carboxylate and hydroxyproline in urine. Cerebral computerized tomography and magnetic resonance imaging were both normal. Electroencephalogram showed a very active epileptic abnormality; partial control of seizures was achieved by two antiepileptics. Increased plasma glycine and ornithine levels are the unique features of our case when compared to the other HP II cases reported in the literature.

1-Pyrroline-5-Carboxylate Dehydrogenase↗