CASE REPORT article
Front. Pediatr.
Sec. Neonatology
A Case of Joubert Syndrome in Twin Pregnancy: MRI Manifestations and Literature Review
Silu Ren 1
Aitong Li 1
Tao Lu 2
Jiyun Yang 2
1. School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
2. Sichuan Academy of Medical Sciences and Sichuan People's Hospital, Chengdu, China
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Abstract
Introduction: Joubert syndrome (JS) is a rare autosomal recessive disorder belonging to the ciliopathies and can cause a series of neurological symptoms after birth. Prenatal diagnosis of this disease is rare, as the results from prenatal ultrasonography for JSRD are relatively nonspecific. Prenatal MRI is usually the preferred diagnostic method. On fetal MRI, it presents as a typical midbrain-hindbrain malformation characterized by the molar tooth sign (MTS). Currently, reports of prenatal MRI diagnosis for JS are rare, with no documented twin gestations. Herein, we report a case of JSRD in a twin pregnancy detected at the 25th gestational week through prenatal MRI, with a review of the etiology, imaging features, and differential diagnosis of JS. Patient presentation: A 31-year-old woman was pregnant at the 25th gestational week with fetal cerebellar vermis hypoplasia suspected from prenatal US. Fetal MRI demonstrated the characteristic MTS, which is the hallmark of JS, and strongly supported the diagnosis at our hospital. The amniotic fluid prenatal diagnosis revealed that the twins had compound heterozygous TMEM67 variants classified as Variants of Uncertain Significance (VUS). The couple finally opted to terminate the pregnancy. Conclusions: Currently, the diagnosis of JS is typically made postnatally. MRI is extremely advantageous for evaluating posterior fossa structural anomalies prenatally. In combination with genetic testing, it can provide guidance for early diagnosis and prenatal counseling.
Summary
Keywords
differential diagnosis, Joubert syndrome and related disorders, Magnetic Resonance Imaging, Molar tooth sign, Posterior fossa malformation, Prenatal Diagnosis
Received
14 December 2025
Accepted
18 February 2026
Copyright
© 2026 Ren, Li, Lu and Yang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Tao Lu
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