Orosomucoid (ORM 1) subtyping and formal genetics

Abstract

Orosomucoid (ORM) phenotyping has been performed in 141 families with 407 children from southwest Germany. Eight families were observed in which duplicated ORM1 genes, F1F2, F1F3, segregated. The family data gave no information about the presence of tandemly duplicated ORM1 F1F4 and ORM1 F1F5 genes. To date, the segregation of the phenotypes of the children agrees with the extended formal model: two ORM1 loci with two common (*F1, *S) and several rare (*F1F2, *F1F3, *F4, *F5) alleles. The parental allele frequencies were calculated by gene counting as ORM1 *F1 = 0.5781, *S = 0.3901, *F1F2 = 0.0195, *F4 = 0.0053, *F1F3 = 00.0035, *F5 = 0.0035.

Subtyping of alkylated human orosomucoid: Evidence for a duplicated gene, ORM1*F2S

“…Desialyzation was performed by adding 30 pL neuraminidase (Clostridium perfringens, Sigma type V, N-2876, 1.8 U/mL) to 10 pL plasma, and then incubating for at least 18 h at 37 "C. Reduction and alkylation were essentially performed according to Luckenbach et nl. [12]. Briefly, after addition of 5 ILL of 0.2 M boric acid/NaOH buffer (pH 9.0) con-taining 8 M urea and 290 mM DTT, samples were incubated for 1 hat 37OC.Finally5 pLofa 590 mM iodoacetamide solution in the same buffer were added and the samples were again incubated at 37 "C for30 min.…”

“…In addition, the pattern in lane 4 also shows bands corresponding to ORMl F1 and ORMl S as the FlF2S individuals reported by Luckenbach etal. [12]. In all individuals a duplication of the band corresponding to ORM2 A is also seen.…”

“…Detection of ORM was done according to the immunoblotting procedure described by Luckenbach etal. [12]. clearly show a band corresponding to ORMl F2 in a position closer to ORMl S than to ORMl F1.…”

“…More recently, Luckenbach etal. [12] demonstrated that a substantial improvement in the detection of the ORMl F2 gene product could be achieved when ORM was chemically modified by reductive cleavage with dithiothreitol (DTT) followed by alkylation with iodoacetamide. Moreover, this method showed the occurrence of a relatively common ORMl FlF2S phenotype and revealed that in all individuals with ORMl F2,a band corresponding to ORMl F1 was also present.…”

“…Desialyzation was performed by adding 30 pL neuraminidase (Clostridium perfringens, Sigma type V, N-2876, 1.8 U/mL) to 10 pL plasma, and then incubating for at least 18 h at 37 "C. Reduction and alkylation were essentially performed according to Luckenbach et nl. [12]. Briefly, after addition of 5 ILL of 0.2 M boric acid/NaOH buffer (pH 9.0) con-Abbreviations: DTT, dithiothreitol; IEF, isoeiectric focusing; ORM, orosomucoid 0 VCH Verlagsaesellschaft mbH.…”