Table 1.

Biochemical Findings in Citrin Deficiency by Phenotype

Phenotype (Age)Blood or Plasma Concentration of Ammonia (µmol/L)Plasma or Serum Concentration of:Plasma or Serum Threonine-to-Serine RatioSerum Concentration of PSTI 2 (ng/mL)
Citrulline 1 (µmol/L)Arginine (µmol/L)
Control18-47 317-43 354-130 31.104.6-20 3
NICCD
(0-6 mos)		603002052.2930
FTTDCD
(>1-11 yrs)		Normal or slightly elevatedNormal or slightly elevatedUsually normalUnknownUnknown
CTLN2
(11-79 yrs)		1524181982.3271

PSTI = pancreatic secretory trypsin inhibitor

1.

Citrullinemia, which can be detected on newborn screening, is the earliest identifiable biochemical abnormality of NICCD [Tamamori et al 2004].

2.

Because the serum PSTI concentration is high in some individuals with NICCD [Tamamori et al 2002] and also in individuals before the onset of CTLN2 [Tsuboi et al 2001], the measurement of serum PSTI concentration may be useful in presymptomatic diagnosis of CTLN2.

3.

Range

From: Citrin Deficiency

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