Prenatal imaging diagnosis of iniencephaly apertus associated with heterotaxy syndrome, alobar holoprosencephaly and myelomeningocele: a case report

Iniencephaly is a predominantly lethal and rare form of neural tube defect characterized by fixed hyperextension of the head, occipital bone abnormalities, and cervical dysraphism. Its estimated incidence ranges from 0.1 to 10 per 10,000 births and is frequently associated with both neurological and non-neurological developmental anomalies. Here, we present the first documented case of iniencephaly apertus in conjunction with heterotaxy syndrome (HS), alobar holoprosencephaly (HPE) and myelomeningocele. Our report describes a 19-year-old primigravida with no significant medical history, whose ultrasound at 19 weeks of gestation identified findings consistent with iniencephaly apertus associated with alobar HPE and myelomeningocele. Fetal magnetic resonance imaging (MRI) at week 20 confirmed these findings and additionally revealed a centrally positioned liver and asplenia, consistent with HS. The pregnancy was terminated at week 21, resulting in a stillborn female with a normal 46 XX karyotype. The family did not consent to an autopsy. Here, we discuss the prenatal ultrasonographic, fetal MRI, and external macroscopic findings of this unique association. This case highlights the importance of prenatal diagnosis in decisions about pregnancy viability and opens a window for future research on factors contributing to the co-occurrence of these rare conditions.