Teaching NeuroImages: The curious case of the brainstem kink

Sumamry

Terminology

Original

  • 25yo F
  • c/c
    • hydrocephalus
  • Prenatal
    • Ex
      • 22w kink
    • DDx
      • α-dystroglycanopathy
      • X-linked hydrocephalus
      • tubulinopathy
  • Postnatal
    • PEx
      • hypotonia
      • macrocephaly
      • optic nerve hypoplasia
    • Dx
      • Walker-Warburg synd (WWs)
        • IPSD gene

A 25-year-old woman presented for routine prenatal ultrasound, which was concerning for severe hydrocephalus. Fetal MRI at 22 weeks showed a brainstem “kink” that suggested arrest or impairment in brain maturation around 7 weeks gestation, a sign of severe neurodysgenesis (figure 1). Differential diagnoses included α-dystroglycanopathies, X-linked hydrocephalus, and tubulinopathies.1 Postnatal imaging (figure 2) and clinical findings of hypotonia, macrocephaly, and optic nerve hypoplasia were consistent with Walker-Warburg syndrome (WWS), confirmed on sequencing of the ISPD gene. WWS is a severe dystroglycanopathy of autosomal recessive inheritance characterized by muscle, eye, and brain abnormalities.2 Death typically occurs within 1 year.

Figure 1

Fig.1

Prenatal imaging Fetal half-Fourier acquisition single-shot turbo spin echo MRI demonstrates a small “kinked” brainstem (arrow) associated with severe supratentorial ventriculomegaly.

Figure 2

Fig.2

Postnatal imaging T2-weighted MRI in (A) sagittal and (B) coronal cuts demonstrates multiple striking anomalies including cobblestoning lissencephaly, pontine and cerebellar hypoplasia, and a kink at the cervicomedullary junction consistent with Walker-Warburg syndrome.