Proposal for the Nomenclature of Human Plasminogen (PLG) Polymorphism

Abstract

Since its discovery, human plasminogen (PLG) polymorphism has received widespread acceptance in population genetics and forensic haematology. Due to the large number of variant alleles described, a PLG reference typing and Plasminogen Symposium was held, at which a nomenclature proposal was inaugurated. The technology of comparing PLG variants was based on isoelectric focusing and subsequent detection by caseinolytic overlay and ‘Western’ blotting. Typing results permitted comparison of so far described variant designations and resulted in a new nomenclature proposal for PLG polymorphism. It is recommended that the two most common alleles found in all investigated races be called: PLG*A (previously also PLG*1) and PLG*B (previously also PLG*2), the known variants with acidic pi: PLG*A1 to *A3, intermediate variants: PLG*M1 to *M5, PLG*M5 being functionally inactive, and basic variants: PLG*B1 to *B3. For future classification of newly discovered variants, samples should be compared at any of the laboratories participating in the reference typing.

Plasminogen Phenotypes in a Japanese Population

“…Furthermore, various PLG alleles have been detected [4], An abnormal plas minogen with an inactive molecule was found in a patient with recurrent thrombo sis [5], and this abnormality was found to be caused by replacement of Ala by Thr at position 600 from the NH2 terminal end [6,7]. The PLG*M5 allele, which leads to the production of an abnormal molecule with little or no activity, is polymorphic in Jap anese [8][9][10][11].…”

Genetic Polymorphism of Plasminogen

“…The comparison of this standardized nomenclature with the designations used up to 1986 is given by Skoda et al (1986).…”

“…In July 1984, at the 18th Congress of the International Society of Blood Transfu sion in Munich, a symposium dealing with the PLG polymorphism took place; during this meeting, a standardised technology for the determination of the PLG gene products and a uniform nomenclature for the designa tion of the PLG alleles have been proposed (Skoda et al 1986). …”

Plasminogen Hemizygosity

“…The structural gene for PLG has been cloned [10], but chromosomal assignment so far was unsuccessful [2,4], Clinical importance of PLG inactivity was first dem onstrated by Aoki et al [1] in a Japanese patient with recurrent thrombosis caused by the variant PLG 'Tochigi'. This variant seems to be identical with an inactive PLG protein (formerly 'MJ\ 'B', or '3') now designated PLG*M5 [18]. Manabe and Matsuda [11] reported a patient with a congenital homozygous deficiency of pro tein C combined with a heterozygous molecular abnor mality of PLG, probably also identical with PLG*M5.…”

“…It comprises two com mon, co-dominant autosomal alleles, PLG*A and PLG*B, and a variety of presently more than eleven rare variants. A uniform nomenclature of PLG alleles has recently been proposed [18]. The structural gene for PLG has been cloned [10], but chromosomal assignment so far was unsuccessful [2,4], Clinical importance of PLG inactivity was first dem onstrated by Aoki et al [1] in a Japanese patient with recurrent thrombosis caused by the variant PLG 'Tochigi'.…”