A Dispermic Chimera with Mixed Field Blood Group B and Mosaic 46,XY/47,XYY Karyotype

Abstract

Chimerism in humans is a rare phenomenon often initially identified in the resolution of an ABO blood type discrepancy. We report a dispermic chimera who presented with mixed field in his B antigen typing that might have been mistaken for the B3 subtype. The propositus is a healthy Korean male blood donor. Neither his clinical history nor initial molecular investigation of his ABO gene explained his mixed field agglutination with murine anti-B. Chimerism was suspected, and 9 short tandem repeat (STR) loci were analyzed on DNA extracted from blood, buccal swabs, and hair from this donor and on DNA isolated from peripheral blood lymphocytes from his parents. The propositus' red blood cells demonstrated mixed field agglutination with anti-B. Exon 6 and 7 and flanking intronic regions of his ABO gene were sequenced and revealed an O01/O02 genotype. B allele haplotype-specific PCR, along with exon 6 and 7 cloning and sequencing demonstrated a third ABO allele, B101. Four STR loci demonstrated a pattern consistent with a double paternal chromosome contribution in the propositus, thus confirming chimerism. His karyotype revealed a mosaic pattern: 32/50 metaphases were 46,XY and 18/50 metaphases demonstrated 47,XYY.

Chimaerism, Mosaicism, and Forensic DNA Analysis

“…From the DNA analysis it could be demonstrated that there was "a pattern consistent with a double paternal chromosome contribution". Further karotyping supported the results, and showed with a mosaic pattern consisting of an additional paternal chromosome reported as 46,XY/47,XYY (16).…”

A 45,X/46,XY DSD (Disorder of Sexual Development) case with an extremely uneven distribution of 46,XY cells between lymphocytes and gonads

“…IVF has been suggested to increase the risk of rare twin-associated anomalies and chimerism (7, 8). Further, one of the major explanations for a rare atypical blood type, such as A1B3, is chimerism (9, 10). In the present case, however, the lack of DNA samples for the biological father prevented efficient genetic analysis to prove the existence of chimerism.…”

Amplification refractory mutation system-PCR is essential for the detection of chimaeras with a minor allele population: a case report

“…Mixed-field agglutination can be seen in various situations, including ABO-incompatible stem cell transplantation, recent transfusions of type-O RBCs in a non-O recipient, rare ABO subgroups such as B 3 and chimaerism 7. In this study, we excluded artificial chimaerism associated with transfusion and transplantation by investigating the propositus’ clinical and transfusion history.…”

“…To examine this discrepancy, the following tests were also performed on the propositus and her family members (mother, sister and brother) with informed consent: (i) ABO serological tests, (ii) ABO genotyping with direct sequencing of exons 6 and 7, (iii) HLA typing and (iv) STR marker analysis. These methods were performed as described previously 2 7…”