Neuroradiologic features of CASK mutations.

Area of Science:

• Neurogenetics
• Developmental Neuroscience
• Medical Imaging

Background:

• CASK gene mutations are linked to X-linked mental retardation, microcephaly, and disproportionate brainstem and cerebellar hypoplasia in females.
• Understanding the specific neuroanatomical features associated with CASK mutations is crucial for diagnosis and management.

Purpose of the Study:

• To investigate and compare the brain structure, particularly the cerebrum and corpus callosum, in female patients with CASK mutations versus controls and patients with pontine hypoplasia.
• To identify potential imaging clues for detecting CASK mutations.

Main Methods:

• Magnetic Resonance (MR) imaging was used to measure the areas of the cerebrum, corpus callosum, pons, midbrain, and cerebellar vermis and hemispheres.
• The ratio of cerebrum to corpus callosum areas was calculated.
• Comparison was made between 5 female patients with CASK mutations, 67 female controls, and 5 patients with pontine hypoplasia.

Main Results:

• Patients with CASK mutations exhibited a normal corpus callosum size, a low cerebrum/corpus callosum ratio, and reduced areas of the cerebrum, pons, midbrain, and cerebellum.
• Patients with pontine hypoplasia showed corpus callosum thinning and a high cerebrum/corpus callosum ratio.
• The normal corpus callosum size in CASK mutation patients can appear as thickening, serving as a potential diagnostic indicator.

Conclusions:

• The neuroanatomical pattern in CASK mutations includes a normal-appearing corpus callosum, which may be mistaken for thickening, alongside reduced cerebrum and posterior fossa structures.
• This distinct imaging finding, specifically the normal corpus callosum size relative to other brain structures, can serve as a valuable clue for identifying CASK gene mutations.
• Differentiating CASK mutations from other causes of pontine hypoplasia based on corpus callosum characteristics is important for accurate diagnosis.