Craniorachischisis totalis

Prenatal diagnosis of craniorachischisis totalis

Craniorachischisis totalis (anencephaly with total open spina bifida) is the most severe form of neural tube defects. The exact aetiology of neural tube defects remains poorly understood. We report a case of a primigravida in her 20s with a fetus in which craniorachischisis totalis was diagnosed during the first-trimester ultrasound at 11 weeks of gestation. The parents opted for pregnancy termination and the diagnosis was confirmed postnatally. Besides the lack of folic acid supplementation during preconception, no other risk factor was found. This case highlights the importance of the first-trimester ultrasound in the diagnosis of severe malformations. The right diagnosis is crucial for future prenatal counselling, yet investigation is still required to better understand the aetiology behind neural tube defects and assess the possibility of underlying genetic features, thus enabling better counselling.

Craniorachischisis with Exencephaly

Neural tube defects can be as mild as spina bifida, to as severe as anencephaly, with only a fraction of these cases presenting as both craniorachischisis and exencephaly. Case report: The G3, P1011 mother was 25-years old, who at an estimated fetal gestational age of 17 weeks had a fetal diagnosis of anencephaly based on a sonogram, resulting in elective pregnancy termination. The female fetus had an open neural tube defect, consisting of craniorachischisis and exencephaly. No abnormalities were noted in any other organs. Conclusion: Although mostly associated with anencephaly, craniorachischisis can also be associated with exencephaly in early pregnancy.

A review of genetic factors underlying craniorachischisis and omphalocele: Inspired by a unique trisomy 18 case

Very few cases of craniorachischisis (CRN) with concomitant omphalocele (OMP) in the setting of trisomy 18 are reported in literature. Solitary midline closure defects are estimated to be more prevalent in trisomy 18 compared to the general population. Neurulation defect comparisons include anencephaly 0-2% versus 0.0206%, spina bifida 1-3% versus 0.0350%, and encephalocele 0-2% versus 0.0082% [Parker et al. (2010); Birth Defects Research. Part A: Clinical and Molecular Teratology, 88:1008-1016; Springett et al. (2015); American Journal of Medical Genetics. Part A, 167A:3062-3069]. The solitary anterior malformation OMP has been reported as high as 6% with trisomy 18 [Springett et al. (2015); American Journal of Medical Genetics. Part A, 167A:3062-3069]. We report the third published case of CRN with concomitant OMP observed in a likely trisomy 18 fetus that screened positive by noninvasive prenatal screening. Furthermore, we review and analyze the current literature to augment understanding of the genetic basis for anterior and posterior closure defects such as CRN and OMP. Although the current genetic lexicon lacks any definitive association with the simultaneous defects presented, previous research elucidated various genes related to anterior or posterior closure interruption individually. By consolidating current research, the authors advance knowledge of interconnected genetic pathology and direct future genetic mapping efforts.