Table 1.

Clinical characteristics of children (N = 21) with adenine phosphoribosyltransferase deficiency at the time of first presentation, classified according to whether the diagnosis of the disorder was made before or after age 18 years.

Females, n (%)	12 (57)
	Diagnosis at age <18 years	Diagnosis at age ≥18 years
Number of patients	15 (71)	6 (29)
Age at first presentation, years	1.5 (0.2–16.5)	4.4 (0.5–7.1)
Age at diagnosis, years	2.5 (0.6–16.5)	35.5 (20.5–42.4)
Diagnostic delay, years	1.2 (0.6–10.4)	29.2 (20.1–39.2)
Reddish-brown diaper stain in infancy	12 (80.0)	1 (16.7)
Kidney stones	7 (46.7)	4 (66.7)
Acute kidney injury	2 (13.3)	1 (16.7)
Chronic kidney disease stage 3–5	0	0
Asymptomatic crystalluria	2 (13.3)	1 (16.7)

Data are presented as number (percentage) and median (range).