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Description
A 5-month-old full-term male patient, born of a non-consanguineous marriage presented to A&E department following parental concerns about abnormal movements and developmental regression.
Development halted at 4 months of age. The patient increasingly showed episodes with flickering of eyes and tonic movements followed by postictal behaviour.
He stopped fixing and following, stopped responding to loud noises, stopped reaching out for objects, and had stopped babbling or making any noises, all of which he had been doing previously. Examination revealed a child with a frog-like posture who appeared very floppy, and with a relatively small head circumference of 41.7 cm (9th centile). Initial blood examinations revealed no significant abnormality. An EEG indicated hypsarrhythmia and a brain MRI was performed. This showed
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Very few sulci with thick cortex;
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Some gyri formation along frontal and temporal lobes (pachygyria);
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Circumferential band of high signal change in parieto-occipital cortex.
This was all consistent with lissencephaly type 1, and genetic tests later confirmed a corresponding LIS1 c. 1050delG mutation. Owing to poor effect with other antiepileptics, Vigabatrin was started in this patient to control his multiple seizures.
Lissencephaly means smooth brain, and is caused by a neuronal migration defect1 resulting in a severe lack of gyrus and sulcus formation. LIS1-associated lissencephaly includes Miller-Dieker syndrome, isolated lissencephaly sequence (ILS) and others,2 which can be established by using fluorescence in situ hybridisation. Prognosis is relatively poor with most children passing away by age 10. Figures 1⇓–3 show the various MRIs and their sequences.
Learning points
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Lissencephaly (smooth brain) represents a group of disorders with neuronal migration defects that are characterised by severely reduced gyral and sulcal formation (aygria or pachygyria).
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Lissencephaly has no cure, and management is largely via supportive treatment.
Footnotes
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Competing interests None.
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Patient consent Obtained.
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Provenance and peer review Not commissioned; externally peer reviewed.