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Familial and sporadic porphyria cutanea tarda: characterization and diagnostic strategies.
Clin Chem. 2009 Apr; 55(4):795-803.CC

Abstract

BACKGROUND

Porphyria cutanea tarda (PCT) occurs in sporadic (sPCT) and familial (fPCT) forms, which are generally clinically indistinguishable and have traditionally been differentiated by erythrocyte uroporphyrinogen decarboxylase (UROD, EC 4.1.1.37) activity. We used UROD gene sequencing as the reference standard in assessing the diagnostic accuracy of UROD activity, evaluating the mutation spectrum of the UROD gene, determining the frequency and disease attributes of PCT and its subtypes in Norway, and developing diagnostic models that use clinical and laboratory characteristics for differentiating fPCT and sPCT.

METHODS

All consecutive patients with PCT diagnosed within a 6-year period were used for incidence calculations. UROD activity analysis, UROD gene sequencing, analysis of hemochromatosis mutations, and registration of clinical and laboratory data were carried out for 253 patients.

RESULTS

Fifty-three percent of the patients had disease-relevant mutations, 74% of which were c.578G>C or c.636+1G>C. The UROD activity at the optimal cutoff had a likelihood ratio (LR) of 9.2 for fPCT, whereas a positive family history had an LR of 19. A logistic regression model indicated that low UROD activity, a high uroporphyrin-heptaporphyrin ratio, a young age at diagnosis, male sex, and low alcohol consumption were predictors of fPCT. The incidence of PCT was 1 in 100 000.

CONCLUSIONS

Two commonly occurring mutations are responsible for the high frequency of fPCT in Norway. UROD activity has a high diagnostic accuracy for differentiating the 2 PCT types, and a model that takes into account both clinical information and laboratory test results can be used to predict fPCT.

Authors+Show Affiliations

Norwegian Porphyria Centre (NAPOS), Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway. aasne.aarsand@helse-bergen.noNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

19233912

Citation

Aarsand, Aasne K., et al. "Familial and Sporadic Porphyria Cutanea Tarda: Characterization and Diagnostic Strategies." Clinical Chemistry, vol. 55, no. 4, 2009, pp. 795-803.
Aarsand AK, Boman H, Sandberg S. Familial and sporadic porphyria cutanea tarda: characterization and diagnostic strategies. Clin Chem. 2009;55(4):795-803.
Aarsand, A. K., Boman, H., & Sandberg, S. (2009). Familial and sporadic porphyria cutanea tarda: characterization and diagnostic strategies. Clinical Chemistry, 55(4), 795-803. https://doi.org/10.1373/clinchem.2008.117432
Aarsand AK, Boman H, Sandberg S. Familial and Sporadic Porphyria Cutanea Tarda: Characterization and Diagnostic Strategies. Clin Chem. 2009;55(4):795-803. PubMed PMID: 19233912.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Familial and sporadic porphyria cutanea tarda: characterization and diagnostic strategies. AU - Aarsand,Aasne K, AU - Boman,Helge, AU - Sandberg,Sverre, Y1 - 2009/02/20/ PY - 2009/2/24/entrez PY - 2009/2/24/pubmed PY - 2009/4/14/medline SP - 795 EP - 803 JF - Clinical chemistry JO - Clin Chem VL - 55 IS - 4 N2 - BACKGROUND: Porphyria cutanea tarda (PCT) occurs in sporadic (sPCT) and familial (fPCT) forms, which are generally clinically indistinguishable and have traditionally been differentiated by erythrocyte uroporphyrinogen decarboxylase (UROD, EC 4.1.1.37) activity. We used UROD gene sequencing as the reference standard in assessing the diagnostic accuracy of UROD activity, evaluating the mutation spectrum of the UROD gene, determining the frequency and disease attributes of PCT and its subtypes in Norway, and developing diagnostic models that use clinical and laboratory characteristics for differentiating fPCT and sPCT. METHODS: All consecutive patients with PCT diagnosed within a 6-year period were used for incidence calculations. UROD activity analysis, UROD gene sequencing, analysis of hemochromatosis mutations, and registration of clinical and laboratory data were carried out for 253 patients. RESULTS: Fifty-three percent of the patients had disease-relevant mutations, 74% of which were c.578G>C or c.636+1G>C. The UROD activity at the optimal cutoff had a likelihood ratio (LR) of 9.2 for fPCT, whereas a positive family history had an LR of 19. A logistic regression model indicated that low UROD activity, a high uroporphyrin-heptaporphyrin ratio, a young age at diagnosis, male sex, and low alcohol consumption were predictors of fPCT. The incidence of PCT was 1 in 100 000. CONCLUSIONS: Two commonly occurring mutations are responsible for the high frequency of fPCT in Norway. UROD activity has a high diagnostic accuracy for differentiating the 2 PCT types, and a model that takes into account both clinical information and laboratory test results can be used to predict fPCT. SN - 1530-8561 UR - https://www.unboundmedicine.com/medline/citation/19233912/Familial_and_sporadic_porphyria_cutanea_tarda:_characterization_and_diagnostic_strategies_ L2 - https://academic.oup.com/clinchem/article-lookup/doi/10.1373/clinchem.2008.117432 DB - PRIME DP - Unbound Medicine ER -