Small posterior fossa in Chiari I malformation affected families is significantly linked to 1q43-44 and 12q23-24.11 using whole exome sequencing

摘要

CM1 and small posterior fossa phenotyping. a CM1 phenotyping midsagittal T1-weighted MR-image showing the cerebellar tonsils (white arrow) extending ≥5 mm below the foramen magnum in a patient with CM1. b Small posterior fossa diagram of the measurements taken in the midsagittal plane, adapted from an earlier, non-copyrighted publication: Heiss JD, Suffredini G, Bakhtian KD, Sarntinoranont M, Oldfield EH. Normalization of hindbrain morphology after decompression of Chiari malformation Type I. J Neurosurg. 2012;117(5):942-6. Measurements (mm) to assess for the small bone phenotype included: supraocciput length (so, internal occipital protuberance to opisthion); clivus length (cl, apex of dorsum sellae to basion); and basiocciput length (bo, the portion of the clivus below the sphenoocipital synchondrosis). Cerebellar tonsillar ectopia (T, maximum extension of the cerebellar tonsils caudal to the foramen magnum) was not used to assess for the small bone phenotype