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Monochorionic diamniotic twins concordant for anencephaly: a case report
Patrick L Wilson1, Jean Ricci Goodman, Katie M Smith
1Section of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
The Journal of Reproductive Medicine
|July 31, 2009
Summary
This study reports a rare case of identical twins both diagnosed with anencephaly, a severe neural tube defect. This finding contributes to understanding the inheritance patterns of anencephaly in twins.
Area of Science:
- Reproductive Medicine
- Developmental Biology
- Genetics
Background:
- Anencephaly, a severe neural tube defect, affects 1.4-4.7 per 10,000 deliveries, often due to failed anterior neuropore closure.
- Identical (monozygotic) twins have a higher risk of congenital malformations.
- Previous twin cases with neural tube defects were discordant, suggesting multifactorial inheritance.
Observation:
- A case of monochorionic diamniotic twins was identified at 22 weeks gestation.
- Prenatal ultrasound revealed anencephaly in both twins, along with other anomalies like ventricular septal defect and renal agenesis.
- Postnatal genetic analysis confirmed identical karyotypes (46,XX) for both twins and the placenta.
Findings:
- Presents a rare instance of monochorionic diamniotic twins concordant for anencephaly.
- This case adds to the limited data on identical twins affected by anencephaly.
- Both twins were diagnosed with anencephaly, indicating a potential shared genetic or developmental pathway.
Implications:
- The concordant presentation challenges previous hypotheses of solely multifactorial inheritance for anencephaly in twins.
- Further research into genetic and epigenetic factors is warranted to explain concordant anencephaly in identical twins.
- Future pregnancies with anencephaly may provide further evidence for Mendelian inheritance patterns.
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