Liver histology in children with glycogen storage disorders type VI and IX.

BACKGROUND: Glycogen storage diseases (GSD) type VI and IX are caused by liver phosphorylase system deficiencies and the two types are clinically indistinguishable. AIM: As the role of liver biopsy is increasingly questioned, we aim to assess its current value in clinical practice. METHODS: We retrospectively reviewed children with diagnosis of GSD VI and IX at a paediatric liver centre between 2001 and 2018. Clinical features, molecular analysis and imaging were reviewed. Liver histology was reassessed by a single histopatologist. RESULTS: Twenty-two cases were identified (9 type VI, 9 IXa, 1 IXb and 3 IXc). Features at presentation were hepatomegaly (95%), deranged AST (81%), short stature (50%) and failure to thrive (4%). Liver biopsy was performed in 19 patients. Fibrosis varied in GSD IXa with METAVIR score between F1-F3 and ISHAK score of F2-F5. METAVIR score was F2-F3 in GSD VI and F3-F4 in GSD IXc. Hepatocyte glycogenation, mild steatosis, lobular inflammatory activity and periportal copper binding protein staining were also demonstrated. CONCLUSIONS: Although GSD VI and IX are considered clinically mild, chronic histological changes of varying severity could be seen in all liver biopsies. Histopathological assessment of the liver involvement is superior to biochemical parameters, but definitive classification requires a mutational analysis.

Laser microdissection microscopy: application to cell culture.

Laser microdissection (LMD) microscopy allows isolation of specific cell populations to target their -molecular profile. There are several different types of LMD microscopes, but they are all based on the same principle. A laser beam is used to cut out cells or tissues of interest from a histological section, cytology preparations, or live cells from tissue cultures. Live cells can be isolated using LMD and processed for downstream molecular work. RNA, DNA, and protein isolation is possible from a small number of cells and the material is suitable for further real-time PCR, ELISA, Western Blotting, and protein microarray analysis.

Ornithine transcarbamoylase deficiency presenting with acute liver failure.

Ornithine transcarbamoylase (OTC) deficiency is the most common hereditary urea cycle disorder. It is an X-linked recessive disorder that usually presents with encephalopathy and hyperammonaemia. We report a 14-month-old female carrier of OTC deficiency, who presented with a history of intermittent vomiting for 5 weeks and irritability and lethargy for 1 week. She was found to be in acute liver failure, with elevated transaminases, coagulopathy and a consistently low urea. Identifying an OTC mutation and ruling out other possible causes of acute hepatic failure confirmed the diagnosis. She was placed on low-protein diet supplemented with essential amino acids, and her liver enzymes, hyperammonaemia and coagulopathy corrected. Three other female patients have been reported with OTC deficiency presenting with severe cryptogenic hepatitis; our patient is unique in that the presentation of her disease was dominated by acute liver failure on a back ground of normal growth and development, no liver enlargement, and mild hyperammonaemia. OTC deficiency should be considered in the differential diagnosis of infants presenting with acute hepatocellular dysfunction, especially in females.