Clinical and genetic spectrum of glycogen storage disease in Iranian population using targeted gene sequencing.

Glycogen storage diseases (GSDs) are known as complex disorders with overlapping manifestations. These features also preclude a specific clinical diagnosis, requiring more accurate paraclinical tests. To evaluate the patients with particular diagnosis features characterizing GSD, an observational retrospective case study was designed by performing a targeted gene sequencing (TGS) for accurate subtyping. A total of the 15 pediatric patients were admitted to our hospital and referred for molecular genetic testing using TGS. Eight genes namely SLC37A4, AGL, GBE1, PYGL, PHKB, PGAM2, and PRKAG2 were detected to be responsible for the onset of the clinical symptoms. A total number of 15 variants were identified i.e. mostly loss-of-function (LoF) variants, of which 10 variants were novel. Finally, diagnosis of GSD types Ib, III, IV, VI, IXb, IXc, X, and GSD of the heart, lethal congenital was made in 13 out of the 14 patients. Notably, GSD-IX and GSD of the heart-lethal congenital (i.e. PRKAG2 deficiency) patients have been reported in Iran for the first time which shown the development of liver cirrhosis with novel variants. These results showed that TGS, in combination with clinical, biochemical, and pathological hallmarks, could provide accurate and high-throughput results for diagnosing and sub-typing GSD and related diseases.

A Rapid Screening Test on Dried Blood for the Neonatal Diagnosis of Tyrosinemia Type I.

BACKGROUND: Tyrosinemia is an inherited metabolic disorder characterized by elevated levels of tyrosine and its metabolites in plasma. Without treatment, the disease will progress to hepatic and renal failure, so that without liver transplantation will cause death in less than 10 years of age. So, early diagnosis and treatment can be life saving and crucial. It means that with early treatment starting in the neonatal period, the patient can have normal life with very few restrictions in diets containing tyrosine and phenylalanine. OBJECTIVES: In this study we wanted to evaluate an easy to perform, rapid and sensitive qualitative test with low cost, as a part of neonatal screening tests to help early diagnosis and treatment of hereditary tyrosinemia. PATIENTS AND METHODS: In this cross sectional study, during the study period (2013 - 2014), 100 patients were selected. Fifty three (53) of these patients had proven tyrosinemia and the other 47 cases biliary atresia, paucity of intrahepatic bile ducts, cytomegalovirus (CMV) hepatitis, galactosemia and storage diseases. RESULTS: There were 2 false negative and 14 false positive cases of hereditary tyrosinemia (HT-1) in the test. Six cases of biliary atresia, 7 cases of paucity of intrahepatic bile ducts and one patient with cytomegalovirus (CMV) hepatitis were falsely positive with the test. Sensitivity of the test was 96.23%, specificity 71.43%, positive predictive value (PPV) 78.46%, and negative predictive value (NPV) 94.59%. CONCLUSIONS: This rapid qualitative test on dried blood sample is an easy, cheap, and feasible method for the screening of hereditary tyrosinemia in neonatal period.