Clinical, Biochemical, and Radiologic Characteristics of Filipino Patients with Glutaric Aciduria Type 1

Abstract

Introduction. Glutaric Aciduria Type 1 (GA1) is an inborn error of metabolism included in the expanded newborn screening of the Philippines. This inborn error of metabolism is caused by glutaryl-CoA dehydrogenase deficiency which is important in the catabolism of lysine, hydroxylysine and tryptophan.Objective. This paper aimed to present the baseline data of patients with GA1 in the Philippines by describing the clinical, biochemical, and radiologic characteristics of Filipino patients with biochemically-confirmed GA1 seen at the Philippine General Hospital from January 2010 to December 2017. The cases of this condition have been increasing and are expected to increase even more with the full coverage of the expanded newborn screening.Methods. This study was a review of the medical records of the GA1 patients managed by the Division of Clinical Genetics, Department of Pediatrics of the Philippine General Hospital (PGH). Biochemical parameters, developmental assessment, neurologic assessment, and radiologic features of the patients were reviewed and analyzed.Results. There were a total of 7 patients with GA1 at the PGH from January 2010 to December 2017. Of the 7 patients, 4 were diagnosed by expanded newborn screening (ENBS) and 3 patients had disease onset prior to diagnosis. Clinical features noted in screened patients include global developmental delay (75%), seizures (50%), dystonia (50%), truncal hypotonia (25%) and macrocephaly (25%). In unscreened patients, macrocephaly was present in 66.67 %, while the other clinical features were present in all of them. Four of the 7 patients had infection and one had vaccination, which may have led to a metabolic crisis and subsequent onset of symptoms. The plasma levels of glutarylcarnitine (C5DC) range from 2.81 to 4.58 umol/L. Grossly elevated urinary excretion of glutarylcarnitine were noted in all patients. Urinary glutaconic acid and 3-hydroxyglutaric acid were also detected in all patients. Both striatal and extra-striatal abnormalities were present in screened and unscreened patients on neuroimaging. The most common being the widening of the sylvian fissure, cerebral atrophy, and white matter abnormalities.Conclusion. Although newborn screening of GA1 and initiation of early management of this condition have been seen important, it is still prudent to continue the appropriate management and to provide timely aggressive emergency treatment in order to improve outcome of patients with GA1. With the recent Philippine Health Insurance (PhilHealth) coverage of the expanded newborn screening, it is expected that physicians will encounter more of the metabolic disorders, including GA1. Hence, it is important that physicians be more aware of the presenting signs and symptoms of this disorder, as well as its management, which can further improve the neurologic and developmental outcomes of these patients.