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.
Glutaric acidemia type 1 (GA1) is an inherited disorder in which the body is unable to completely break down the amino acids lysine, hydroxylysine and tryptophan. Excessive levels of their intermediate breakdown products (glutaric acid, glutaryl-CoA, 3-hydroxyglutaric acid, glutaconic acid) can accumulate and cause damage to the brain (and also other organs), but particularly the basal ganglia, which are regions that help regulate movement. GA1 causes secondary carnitine deficiency, as glutaric acid, like other organic acids, is detoxified by carnitine. Mental retardation may occur. GA1 is an autosomal recessive disorder caused by deficiency of the enzyme glutaryl-CoA dehydrogenase (GCDH), encoded by the GCDH gene. Signs and symptoms
The severity of glutaric acidemia type 1 varies widely; some individuals are only mildly affected, while others suffer severe problems. GA1 can be defined as two clinical entities: GA-1 diagnosed at birth or pre-birth and managed through dietary restrictions, and GA-1 diagnosed after an encephalopathic crisis. A crisis may occur under both headings, but the care of individuals diagnosed before a crisis can be managed to avoid most or all injury. GA1 without encephalopathic crisis
Macrocephaly
Babies with glutaric acidemia type 1 often are born with unusually large heads (macrocephaly). Macrocephaly is amongst the earliest signs of GA1. It is thus important to investigate all cases of macrocephaly of unknown origins for GCDH deficiency, given the importance of the early diagnosis of GA1. Macrocephaly is a pivotal clinical sign of many neurological diseases.