Dizygotic Twins of Different Gender with Concordant Myelomeningocele: A Case Report and Review of the Literature

Introduction: Myelomeningocele (MMC) is a common subtype of congenital neural tube defects (NTD). Twins show higher rates of NTD, whereas the concordance of spina bifida in dizygotic twins is extremely rare.

Methods: We present a case of dizygotic unlike-sex twins presenting with concordant MMC, live-born and surgically treated within 48h of life. For further analysis of a possible underlying genetic cause, a genetic analysis of the twins is being performed.

Results: Dizygotic twins of different gender were born at term to a 35-year-old woman after an uneventful pregnancy. Due to infertility caused by endometriosis, the twins were conceived through ICSI without preimplantational diagnostic. There was no family history of congenital malformations or consanguinity. Folic acid was supplemented periconceptually and throughout the whole pregnancy, while a mild gestational diabetes was treated with dietary cost only. At 18 weeks of gestation, both twins were diagnosed with a lumbosacral MMC by ultrasound. The known MMC was accompanied by ventriculomegaly and Arnold-Chiari malformation type II. Both twins underwent successful surgical repair of the MMC 48 hours after birth, while due to progressing hydrocephalus both underwent the insertion of a ventriculoperitoneal shunt 1 week later. The further postoperative course was uneventful. The genetic analysis is still ongoing and will be presented.

Conclusion: Concordance of MMC in twins is a rare finding. Only 18 pairs of twins, of which 8 were dizygotic twins, have been described so far. Results of genetic analysis in twins with MMC is lacking in all reports so far. We will present a review of the literature, the results of our genetic analysis and discuss possible implications of these genetic results.