Differential Trends of T-cell Receptor and Kappa-Deleting Recombination Excision Circles in Dichorionic Twins
Background:
In April 2023, T-cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC) were added to the expanded neonatal screening panel in Tokyo, Japan.
Methods:
We observed dichorionic twins with divergent TREC and KREC trends despite no maternal differences. Levels were monitored across screenings.
Results:
The first-born had normal TREC and KREC, whereas the second-born showed undetectable TREC with low KREC at first screening. Further immunological evaluation found no abnormalities. By the fourth screening on day 190, TREC and KREC levels in the second-born normalized.
Conclusions:
TREC and KREC levels may be influenced by the in utero environment.
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