A case report recently published in the Medical Journal Armed Forces India described a pair of identical male twins diagnosed with anti-c hemolytic disease of the fetus and newborn (HDFN) with discordant clinical courses.
The twins shared a single placenta, had the same antigen status and had positive direct antiglobulin tests (DAT). Nevertheless, one twin remained relatively stable after birth, while the second had more severe anemia and required a blood transfusion.
The infants were born at 35 weeks and five days gestation via cesarean section. Ultrasounds did not show any evidence of twin-to-twin transfusion syndrome or differences in fetal growth. Because the twins were born premature and exhibited respiratory distress, they were admitted to the neonatal intensive care unit.
Upon admission, the respiratory symptoms subsided, and both individuals tolerated feeds normally.
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On the second day of life, both twins developed jaundice. The first twin underwent phototherapy and intravenous immunoglobulin (IVIG) therapy. He did not receive any blood transfusions while in the NICU.
In addition to having jaundice, the second twin was anemic on day two. While he received phototherapy and IVIG, his hemoglobin levels continued to decline, requiring a blood transfusion.
Evaluation revealed very high anti-c antibody levels in the mother. These antibodies reacted strongly with the twins’ red blood cells, confirming that they were targeting and destroying the infants’ blood cells.
The patients were discharged from the hospital in stable condition. At the end of the first and second months of life, both twins received blood transfusions with c-antigen-negative blood units. Following the transfusions, bilirubin levels stabilized, and the patients experienced normal growth thereafter.
The researchers provided several potential explanations for this discrepancy. It is possible that antibody transfer through the placenta may be uneven or that antigen expression on fetal red blood cells may vary. Furthermore, although the twins were identical, they may still display subclinical differences contributing to disease severity.
“This case underscores that even genetically identical twins can experience substantially different disease severity in minor Rh antigen-related [HDFN], emphasizing the need for vigilant, individualized monitoring,” the authors concluded.
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