Quite often, the presenting symptom of<unk><unk>  <unk>  is myopia which progresses to night blindness. The onset of myopia is often in early childhood. Ophthalmological findings in affected individuals include constricted visual fields, posterior subcapsular cataracts (can begin in late teens), elevated dark adaptation thresholds and decreased or absent electroretinographic responses. Symptoms of<unk>  are progressive, and between the ages of 45 and 65, most affected individuals are almost completely blind. In some cases, affected individuals will present in the neonatal period with disease that closely mimics a classic urea cycle defect, such as<unk>  transcarbamylase deficiency, as the block in<unk>  metabolism leads to secondary dysfunction of the urea cycle. These individuals present with hyperammonemia, poor feeding, failure to thrive and increased excretion of orotic acid.
Ornithine aminotransferase deficiency
Glutaminase deficiency
Malonyl-CoA decarboxylase deficiency
Pyruvate kinase deficiency
Arginine:glycine amidinotransferase deficiency
3-Hydroxyisobutyryl-CoA deacylase deficiency
3-Methylcrotonyl-CoA carboxylase deficiency
Transaldolase deficiency