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Squared superior portion of helix

MedGen UID:
Concept ID:
HPO: HP:0030026


Flattening instead of curving or rounded superior helix, allowing the superior helix to run more horizontally than usual. [from HPO]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVSquared superior portion of helix

Conditions with this feature

Periventricular nodular heterotopia 9
MedGen UID:
Concept ID:
Disease or Syndrome
Periventricular nodular heterotopia-9 (PVNH9) is an autosomal dominant neurologic disorder characterized as a malformation of cortical development. Anterior predominant PVNH, thin corpus callosum, and decreased white matter volume are found on brain imaging, but the clinical effects are variable. Most patients have impaired intellectual development and cognitive defects associated with low IQ (range 50 to 80), learning disabilities, and behavior abnormalities. Some patients develop seizures that tend to have a focal origin. However, some mutation carriers may be less severely affected with borderline or even normal IQ, suggesting incomplete penetrance of the phenotype (summary by Heinzen et al., 2018, Walters et al., 2018). For a discussion of genetic heterogeneity of periventricular nodular heterotopia, see 300049.

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