Junctional Neural Tube Defect (JNTD): A Rare and Relatively New Spinal Dysraphic Malformation

Area of Science:

• Developmental biology
• Neuroscience
• Embryology

Background:

• Junctional neurulation is a critical intermediary step in embryonic development, connecting primary and secondary neurulation.
• The precise molecular mechanisms governing junctional neurulation remain incompletely understood.
• Junctional neural tube defects (JNTDs) represent a rare congenital anomaly with unique anatomical and functional characteristics.

Purpose of the Study:

• To describe the clinical, neuroimaging, and electrophysiological features of junctional neural tube defects (JNTDs).
• To present a hypothesis regarding the embryogenetic mechanism underlying JNTDs.
• To consolidate existing knowledge on this recently described entity.

Main Methods:

• Review of clinical case series describing patients with JNTDs.
• Analysis of neuroimaging findings in affected individuals.
• Electrophysiological assessments to evaluate neural function.

Main Results:

• JNTDs are characterized by a physically separated primary and secondary neural tube (conus).
• Affected individuals exhibit functional disconnection from rostral corticospinal pathways.
• Multiple case reports have reinforced the recognition of JNTD as a distinct entity.

Conclusions:

• JNTD is a valid clinical entity resulting from abnormalities during junctional neurulation.
• The distinct separation and functional disconnection highlight a specific developmental failure.
• Further research into the molecular underpinnings of junctional neurulation is warranted.