Estudio molecular del déficit de piruvatocinasa eritrocitaria en 15 pacientes con anemia hemolítica crónica

BACKGROUND: Identification of RBC pyruvate-kinase (PK) gene mutations by polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP) followed by PK gene sequencing in positive cases has been assessed and the results obtained with a preliminary study of 15 unrelated patients of Spanish origin are presented. PATIENTS AND METHODS: Patients have been classified into two different groups: group 1, propositus (15 cases), and group 2, relatives of the patients included in group 1 (10 males and 5 females). In group 1, a PCR was followed by SSCP and sequencing, and in group 2, the PCR was followed by digestion with specific restriction endonucleases (PCR-ER). RESULTS: Group 1: from 15 patients included in the study 2 were identified as homozygous, 4 as heterozygous and 9 as compound heterozygous. In this group, were identify 26 affected alleles with 11 different mutations: T¹⁴⁵⁶ 10 alleles (38.6%), T⁷²¹ 3 alleles (11.6%), A¹⁰¹⁰, C⁵¹⁴, C¹⁰¹⁵ and T¹²²³ 2 alleles (7.7%), and C¹⁰⁷⁰, A¹²⁹¹, T¹⁵⁰⁸, A¹⁵⁹⁵ y T¹⁶⁷⁵ one allele. Relatives from 8 out of 15 patients from group 1 showed the following pattern: homozygous (one case), heterozygous (10 cases), compound heterozygous (2 cases) and normal (2 cases). CONCLUSIONS: SSCP procedure followed by direct gene sequencing in positive cases is fast and simple enough to allow the identification of PK deficient variants, avoiding the need of biochemical characterisation of semipurified deficient enzyme, which is more cumbersome and time consuming. In addition, the PCR-ER method is a very useful tool for screening of the most frequent molecular variants, as well as, for the detection of the carrier condition of this enzymopathy (family studies).