This includes urine organic acid analysis, looking for glutaric acid and 3-hydroxyglutaric acid. Plasma and urine acylcarnitine analysis can also be informative. Molecular analysis, including gene sequencing and copy number analysis of GCDH, can be performed to confirm the diagnosis. Molecular testing can also provide information for family planning and prenatal testing, if desired. Treatment
Correction of secondary carnitine depletion
Like many other organic acidemias, GA1 causes carnitine depletion. Whole-blood carnitine can be raised by oral supplementation. However, this does not significantly change blood concentrations of glutarylcarnitine or esterified carnitine, suggesting that oral supplementation is suboptimal in raising tissue levels of carnitine. Clinical nutrition researchers have likewise concluded that oral carnitine raises plasma levels but does not affect those in muscles, where most of it is stored and used.In contrast, regular intravenous infusions of carnitine cause distinct clinical improvements: "decreased frequency of decompensations, improved growth, improved muscle strength and decreased reliance on medical foods with liberalization of protein intake. "Choline increases carnitine uptake and retention. Choline supplements are inexpensive, are safe (probably even in children requiring anticholinergics) and can increase exercise tolerance, truncal tone and general well-being, providing evidence of the suboptimal efficiency of carnitine supplementation alone. Selective precursor restriction
Dietary control may help limit progression of the neurological damage. Lysine
Lysine restriction, as well as carnitine supplementation, are considered the best predictors of a good prognosis for GA1. This excludes, however, patients who already suffered an encephalopathic crisis, for whom the prognosis is more related to the treatment of their acquired disorder (striatal necrosis, frontotemporal atrophy).
When suspected and in the absence of confirmed diagnosis (through genetic sequencing), it is critical that the individual maintain a diet restrictive of all proteins and that blood sugars be monitored rigorously. The WHO now considers this disease entirely manageable. Epidemiology
GA1 can be described as a metabolic disorder, a neurometabolic disease, a cerebral palsy or a basal ganglia disorder (it may also be misdiagnosed as shaken baby syndrome). Depending on the paradigm adopted, GA1 will mostly be managed with precursor restriction or with neurorehabilitation. So-called "orphan diseases", such as GA1, can be adopted into wider groups of diseases (such as carnitine deficiency diseases, cerebral palsies of diverse origins, basal ganglia disorders, and others); Morton at al. (2003b) emphasize that acute striatal necrosis is a distinctive pathologic feature of at least 20 other disorders of very different etiologies, including, HIV encephalopathy–AIDS dementia complex, pneumococcal meningitis, hypoadrenal crisis, methylmalonic acidemia, propionic acidemia, middle cerebral artery occlusion, hypertensive vasculopathy, acute Mycoplasma pneumoniae infection, 3-nitropropionic acid intoxication, late-onset familial dystonia, cerebrovascular abrupt and severe neonatal asphyxia ("selective neuronal necrosis"). In a cohort of 279 patients who had been reported to have GA1, 185 were symptomatic (two-thirds); being symptomatic was seen as an indication of low treatment efficacy. Screening of those known to be at high risk, neonatal population screening and a diagnosis of macrocephaly are the ways to identify bearers of the GCDH mutation who are not frankly symptomatic.