Pyridoxine-dependent Epilepsy caused by a Novel homozygous mutation in PLPBP Gene.

Seizures in newborn infants may be the first finding of hereditary metabolic diseases. Pyridoxine-dependent epilepsy (PDE) is a treatable disorder associated with defects in the one of ALDH7A1, PNPO, or PLPBP genes and it is uncommon but progresses with persistent seizures in the neonatal and infancy period. The seizures are generally resistant to traditional antiepileptic drugs and show a dramatic response to high-dose pyridoxine. In 2016, mutations were reported in PLPBP (previously known as PROSC) gene, which encodes pyridoxal phosphate homeostatic protein (PLPHP).When early-onset antiepileptic resistant seizures are not treated, clinical findings emerge including the development of encephalopathy, congenital microcephaly, and subsequent retardation of psychomotor development. The present case is a 33-month-old female infant with seizures starting from postnatal day 1, who did not respond to traditional anti-epileptic drugs but responded to pyridoxine treatment. In the genetic tests, homozygote c.695 C > T (p.Ala232Val) mutation was determined in the PLPBP gene, which has not been previously identified. Since a specific treatment was found, this case is reported with the aim of emphasizing the need to consider pyridoxine dependence, which is one of the vitamin-dependent metabolic encephalopathies, in the differential diagnosis of epilepsy patients.

Current status of the congenital hypothyroidism neonatal screening program in Adana Province, Turkey.

BACKGROUND: Congenital hypothyroidism (CH) is a common cause of mental retardation; it has a worldwide incidence ranging from 1:3000 to 1:4500 live births. Predictably, an increase in the reported incidence of primary CH occurs when the cut-off levels of thyroid-stimulating hormone are lowered. We aimed to evaluate the results of a congenital hypothyroidism screening program and current status in this study. METHODS: Analysis results of 1300 infants who were referred to the endocrinology polyclinic because of suspected CH within the scope of the Ministry of Health National Neonatal Screening Program were retrospectively evaluated. RESULTS: The diagnosis of CH and initiation of treatment were both done in 223 (18.5%) and 10 (0.8%) infants as a result of the initial evaluation and follow-up, respectively. The mean capillary and venous thyroid-stimulating hormone (TSH) levels of 223 patients were 40.78 (5.5-100) µIU/mL and 67.26 (10.7-100) µIU/mL, respectively. These patients' mean heel prick time was 8.65 (0-30, median: 7) days. The mean age of the 223 infants whose treatment was initiated as a result of the initial evaluation was 19.87 (4-51, median: 20) days, and the mean age of the infants whose treatment was started at follow-up was 43.71 (29-65) days. The duration between heel prick time and venous TSH time was 11.10 (2-28, median: 11) days and was longer than planned (3-5 days). CONCLUSIONS: Although the duration for the diagnosis and initiation of CH treatment were markedly reduced with the implementation of the screening program in Turkey compared to those before the implementation of the screening program, we have not yet achieved the ideal time (≤14 days).

p.Val452Ile mutation of the SLC25A13 gene in a Turkish patient with citrin deficiency.

Seker-Yilmaz B, Kör D, Tümgör G, Ceylaner S, Önenli-Mungan N. p.Val452Ile mutation of the SLC25A13 gene in a Turkish patient with citrin deficiency. Turk J Pediatr 2017; 59: 311-314. Citrin deficiency is an autosomal recessive metabolic disorder, which is caused by pathogenic mutations in the SLC25A13 gene on chromosome 7q21.3, as the causative gene that encodes the liver type aspartate/glutamate carrier isoform 2 (AGC2). One of the main clinical presentations is neonatal intrahepatic cholestatic hepatitis caused by citrin deficiency. We report a Turkish child presented with prolonged neonatal jaundice associated with elevated plasma citrulline and galactosuria. NICCD was suspected at this point and mutation study of SLC25A13 showed that she was homozygous for the missense NM_014251.2:c.1354G > A (NP_055066.1:p.Val452Ile) (dbSNP: rs143877538) mutation. Dramatic response was observed to the dietary treatment with medium-chain triglycerides containing formula, ursodeoxycholic acid and fat-soluble vitamin supplementation. The minor allele frequency of this variant was given as nearly as 0.01 in the South Asian population; it seems like a disease causing variant. This is the first report of this variant in the Turkish and European population.

Brown-Vialetto-Van Laere syndrome: two siblings with a new mutation and dramatic therapeutic effect of high-dose riboflavin.

Brown-Vialetto-Van Laere syndrome (BVVLS) is a rare and severe neurometabolic disease. We present two siblings with BVVLS with a novel homozygous mutation in SLC52A3 (formerly C20orf54) gene. The first sibling was admitted with respiratory insufficiency and required mechanical ventilation. After administration of a high dose of riboflavin, all his clinical symptoms were resolved, which also strongly suggested the diagnosis of BVVLS. The second sibling was also found to have the same genetic mutation as her brother. Although she was symptom-free, riboflavin was initiated empirically. On follow-up, she developed no neurologic or metabolic problems with entirely normal growth and development. BVVLS should be considered in the differential diagnosis of unexplained neurologic symptoms such as polyneuropathy and respiratory insufficiency, as BVVLS and multiple acyl-CoA dehydrogenation defect have broadly overlapping symptoms. Furthermore, our cases once again suggest that with proper diagnosis and early high-dose riboflavin treatment, complete reversal of neurologic deficits in BVVLS is possible.

Homozygous familial hypobetalipoproteinemia: A Turkish case carrying a missense mutation in apolipoprotein B.

The autosomal co-dominant disorder familial hypobetalipoproteinemia (FHBL) may be due to mutations in the APOB gene encoding apolipoprotein B (apoB), the main constituent peptide of chylomicrons, very low and low density lipoproteins. We describe an 11month-old child with failure to thrive, intestinal lipid malabsorption, hepatic steatosis and severe hypobetalipoproteinemia, suggesting the diagnosis of homozygous FHBL, abetalipoproteinemia (ABL) or chylomicron retention disease (CMRD). The analysis of candidate genes showed that patient was homozygous for a variant (c.1594 C>T) in the APOB gene causing arginine to tryptophan conversion at position 505 of mature apoB (Arg505Trp). No mutations were found in a panel of other potential candidate genes for hypobetalipoproteinemia. In vitro studies showed a reduced secretion of mutant apoB-48 with respect to the wild-type apoB-48 in transfected McA-RH7777 cells. The Arg505Trp substitution is located in the ßα1 domain of apoB involved in the lipidation of apoB mediated by microsomal triglyceride transfer protein (MTP), the first step in VLDL and chylomicron formation. The patient's condition improved in response to a low fat diet supplemented with fat-soluble vitamins. Homozygosity for a rare missense mutation in the ßα1 domain of apoB may be the cause of both severe hypobetalipoproteinemia and intestinal lipid malabsorption.

Primary systemic carnitine deficiency: a Turkish case with a novel homozygous SLC22A5 mutation and 14 years follow-up.

Systemic primary carnitine deficiency is an autosomal recessive disorder caused by the deficiency of carnitine transporter. Main features are cardiomyopathy, myopathy and hypoglycemic encephalopathy. We report a Turkish case with a novel SLC22A5 gene mutation presented with a pure cardiac phenotype. During the 14-year follow-up study, cardiac functions were remained within a normal range with oral L-carnitine supplementation.