Disappearance of a 47,XX,C+ Leucocyte Cell Line in an Infant Who Had Previously Exhibited 46,XX/47,XX,C+ Mosaicism

Abstract

Follow-up observations are reported on an infant with numerous phenotypic abnormalities who had been reported at 7 months of age to have an extra C group autosome in 17% of her peripheral leucocytes. Examination of the patient at age 2½ years revealed that the physical findings were essentially unchanged, except for increased prominence of the sixth, seventh, and eighth thoracic vertebrae. The abnormal cell line was found to have disappeared from her leucocytes in cultures repeated at ages 2½ and 2[unknown] years. Analysis of bone marrow metaphases showed that 7% were of the 47,XX,C+ karyotype. Other reported examples of disappearing abnormal cell lines are reviewed. These findings may help explain those cases having the clinical appearance of a syndrome associated with chromosomal abnormality, but whose karyotypes are normal. It is possible that a mosaicism existed during fetal life, and that the cytogenetically abnormal cell line caused abnormal organogenesis prior to its later disappearance.