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A case of hyperinsulinism/hyperammonaemia syndrome with reduced carbamoyl‐phosphate synthetase‐1 activity in liver: A pitfall in enzymatic diagnosis for hyperammonaemia
Author(s) -
Ihara K.,
Miyako K.,
Ishimura M.,
Kuromaru R.,
Wang H.Y.,
Yasuda K.,
Hara T.
Publication year - 2005
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/s10545-005-0084-z
Subject(s) - hyperinsulinism , medicine , endocrinology , congenital hyperinsulinism , carbamoyl phosphate synthetase , enzyme , biology , biochemistry , diabetes mellitus , insulin resistance
Summary We report a patient who was first diagnosed as having congenital carbamoyl‐phosphate synthetase‐1 (CPS‐1) deficiency on the basis of significantly low CPS‐1 activity in the liver at 1 year of age. We then started therapy against hyperammonaemia with little effect and, at the age of 15 years, we analysed the GLUD1 gene and found a previously reported gain‐of‐function mutation in the gene, resulting in a change of her diagnosis to hyperinsulinism/hyperammonaemia (HI/HA) syndrome. This case demonstrates that low CPS‐1 activity in liver, however significant it might be, does not always come from a primary CPS‐1 deficiency and that we have to take into consideration the possibility of a secondary CPS‐1 deficiency, such as HI/HA syndrome.