No abstract

Previous electrophoretic studies of the A and B subunits of factor XIII have revealed considerably genetic heterogeneity. The present work investigates the electrophoretic forms and quantitates the A and B subunits in a family with inherited factor XIII deficiency. The data indicate that the deficiency in this family is due to a null allele at the locus controlling the A subunit. All family members were found to have decreased levels of B subunit. The data also indicate that there is no difference in thrombin activated transamidase activity between normal individuals with the three commonly occurring electrophoretic phenotypes of the A subunit.

Summary: Factor XIII deficiency in three sisters is reported together with studies of the inheritance based on the transamidase activity utilising 14C‐glycine ethyl ester. The classical clinical picture, treatment and the findings in this family are discussed.

A 43-yr-old male patient with primary acquired red cell hypoplasia was studied over a course of 5 yr. Repeated bone marrow examinations showed marrow replacement by an abnormal cell clone characterized by deletion of most of the long arm of a B group chromosome (Bq-). Chromosomes of blood lymphocytes and skin fibroblasts were normal. 55Fe labeling of bone marrow metaphases demonstrated the abnormal chromosome in developing erythroid cells, and it was considered to be present in the common erythroid-myeloid precursor stem cell and its derivatives. Studies of bone marrow cell proliferation using 3H-thymidine autoradiography combined with DNA cytochemistry demonstrated a specific breakdown of erythroid differentiation at the stage of the early polychromatic normoblast. It is suggested that red cell hypoplasia was a function of the abnormal clone that replaced normal erythropoietic stem cells of the bone marrow, but proved to be defective in the metabolism required for red cell production. Such replacement of normal bone marrow tissue, presumably associated with the somatically acquired cytogenetic change, is regarded as a neoplastic though nonmalignant development. The patient died from complications of influenzal pneumonia without evidence of tumor or leukemia.

Forty‐four per cent of 110 unselected patients presenting with acute myeloid, lymphatic, or stem cell leukemia had a karyotypically abnormal, clonal cell line in the bone marrow, and about 60% of these patients also had apparently normal, diploid cells coexisting with the abnormal cells. The karyotypic changes were diverse and distinctive for each patient, but acute lymphatic leukemia tended to hyperdiploidy. The karyotypic changes showed low involvement of F chromosomes, and some excess involvement of C and G chromosomes. There was little evidence of karyotypic evolution. Where therapy induced full remission, abnormal cell lines tended to be replaced by diploid cells. The incidence of karyotypic abnormality at diagnosis was not related to patient age, sex, or type of leukemia. Significantly, the presence of karyotypic abnormality did not influence the chance of leukemic remission or patient survival, except that male patients with C chromosome deficiency survived on average three times longer than those with additional C chromosomes. This study and a review of five other major studies led to the conclusion that karyotypic abnormalities of acute leukemia have little or no etiological, clinical or hematological significance, and do not influence patient survival. It would appear that cell lines characterized by karyotypic abnormality rarely determine leukemic progression, but develop within limits set by a prescribed and individual cell environment.