A novel mutation causing mild, atypical fumarylacetoacetase deficiency (Tyrosinemia type I): a case report

Table 1 Liver enzyme activities

	Biopsy I	Biopsy II	Tyr type III	Controls
FAH	2.2	1.8	33	41 (38.8-46.4)
4-HPD	11	8.7	0.2	15 (10.8-18.4)
ASAT	3472	2669	2490	1731,1641
ALAT	700	810	1340	665, 1034
LDH	3315	2223	3420	3755, 3045

Column 1 shows the result of a first biopsy in the presented patient (at diagnosis), the second column of a confirmatory biopsy in the same patient. Column 3 shows the results in a type III tyrosinemia, for comparison. The last column shows control values. FAH is clearly decreased, but measurable in both biopsies in our patient (approx. 5% of normal). 4-HPD is unexpectedly not equally decreased as would be expected in type I tyrosinemia, also contrasting with the value measured in the type III tyrosinemia biopsy. The fact that 4-HPD is not decreased, is compatible with the absence of SA and SAA in our patient. ASAT, ALAT and LDH are internal controls, demonstrating the quality of the tissue samples used.
FAH: fumarylacetoacetate hydrolase; 4-HPD: 4-hydroxyphenylpyruvate dioxygenase; ASAT: aspartate transaminase; ALAT: alanine transaminase; LDH: lactate dehydrogenase

ISSN: 1750-1172