This gene encodes a centrosome and spindle pole associated protein. The encoded protein plays a role in cell-cycle progression and spindle organization, regulates cytokinesis, interacts with Nephrocystin 8 and is required for cilia formation. Mutations in this gene result in primary cilia abnormalities and classical Joubert syndrome. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [From RefSeq]

The CSPP1 gene is located on the long arm of chromosome 8.  It spans an approximate length of 134 kb and has a coding region consisting of 35 exons.  Alternatively spliced transcript variants result in 2 different isoforms of the CSPP1 protein, namely CSPP1-L and CSPP1-S.  CSPP1-L, the longer isoform, consists of 1221 amino acids and has a molecular mass of 142 kDa.  CSPP1-S has 294 additional amino acids at its N-terminal end and an insertion of 51 amino acids between its coiled coil domains.  Expression of the CSPP1 gene is found to be high in the adult and fetal brain with enrichment in the cerebellum.  Homozygous and compound heterozygous mutations in the CSPP1 gene associated with JBTS21 syndrome result in frameshift and permanent terminations or amino acid substitutions.