Succinylacetone was not detected. Histology Patient 1 underwent liver biopsy at 55 days of age. Abnormal aminograms persisted for a couple of months but then improved, and 2-3 months later, the cholestasis improved. All biochemical abnormalities normalized by the age of 12 months. Follow-up has been maintained for 18 months to 8 years.
All patients are alive and show no developmental delay or neurologic abnormalities.
The principal features of the present cases were abnormal aminograms showing more than 10-fold increases in citrulline concentrations beyond the upper limit of normal. We suspected that these abnormalities might be related to CTLN2, so we obtained informed consent from the parents to perform genetic diagnosis. We treated three patients who presented with adult-onset type II citrullinemia in the neonatal period. We can conjecture that these clinical features represent a neonatal manifestation of CTLN2, but molecular analyses are still pending because of the inavailability of DNA samples from these patients. Overall, CTLN2 has been diagnosed exclusively in Japan.