J.A. Böök

Association Between Congenital Heart Malformation and Chromosomal Variations1

A family is described in which mother rind son both displayed auricular septal defects of the secundum type while father and daughter had no cardiovascular disorders. The karyotypes of these individuals were analysed by the cell culture method using biopsies from bone marrow and skin. The majority of the cells from the mother had 47 chromosomes and she was apparently trisomic [19‐201. A similar additional chromosome of group [19‐201 wasfound in the cells derived from the son.

Chromosome and chromatid-type aberrations induced by cobalt60 irradiation and tritiated uridine in human leukocyte cultures

Human short term leukocyte cultures have been exposed to Co60 and H3-uridine irradiation. At the time of their first mitotic event the cells are collected. In the cultures treated with H3-uridine mainly breaks of chromatid type are found, whereas the Co60 irradiated cells have only breaks of chromosome type as long as the irradiation takes place before the onset of DNA synthesis. It is inferred that H3-uridine causes damage to localized single stranded DNA loops separated during transcription in RNA synthesis and inaccessible to repairing. The results are interpreted as an indication that the chromosome (chromatid) continuity is dependent on one DNA double helix strand and that the subunits of the chromosome, as revealed by radiation, is in fact single-stranded DNA.

Chromosomal Abnormality in a Mongolism-Like Syndrome1

The cytogenetical and clinical observations of a 4 year old girl with a mongolism‐like syndrome are reported. The patient showed a moderate mental and physical retardation. Some signs and symptoms considered characteristic of mongolism were present. Others, such as the dermal patterns of hands and feet, rather contradict this diagnosis. In addition the patient had a bilateral dislocation of the hips and unspecific signs of retinal degeneration. There were no signs of abnormal sexual development.