Miller-Dieker syndrome

The Miller-Dieker syndrome (MDS) or is a rare chromosomal anomaly and is one of the conditions considered part of lissencephaly type I (classic) ⁶. 

Clinico-pathological spectrum

Features include

• CNS
  • neuronal migrational anomalies : lissencephaly type I
  • prominent sub arachnoid spaces
  • widened cerebral ventricles
• cranio-facial
  • microcephaly
  • calvarial thickening
  • bi-temporal pitting
  • prominent occiput
  • micrognathia ⁵
  • microgenia
  • auricular dysplasia
  • flared nostrils
• other
  • corneal clouding

Pathology

Genetics

It often results from a defect in chromosome 17p13.3 with partial loss of this short arm. It is thought to carry an autosomal dominant inheritance.

Associations

• congenital cardiac anomalies ⁴
• congenital renal anomalies
• cryptorchidism ⁴

Radiographic features

Antenatal ultrasound

May show many of the above clinico-pathological features. There may also be evidence of intra-uterine growth restriction (IUGR).

MRI

The features are those of type I lissencephaly. The brain is usually grossly abnormal in outline, with only a few shallow sulci and shallow Sylvian fissures, taking on an hour glass or figure-8 appearance on axial imaging. The cortex is markedly thickened measuring 12 - 20mm (rather than the normal 3 - 4mm) ⁷.

Etymology

Named after J Q Miller ³ and H Dieker. 

Prognosis

The overall prognosis is poor with most fetuses not surviving beyond infancy. There may be recurrence rate of ~ 25% for future pregnancies.

See also

• classification system for malformations of cortical development
• lissencephaly
• lissencephaly type I - subcortical band heterotopia spectrum