gene, located on the long arm of chromosome 1. CENPF codes for centromere protein F. Centromere proteins are involved in the separation of chromosomes during cell division. This is through forming part of kinetochores, which are disc-shaped protein complexes that allow the centromeres of chromosomes (in the dividing form, known as chromatids) to attach to microtubules in the cell (forming what is called the spindle apparatus). This allows the microtubules to pull the chromosomes apart in the process of dividing the cell. Mutations in this gene lead to impaired cell division during early development. Mitosis has been found to take longer when CENPF is mutated. Microtubules are protein structures that are part of the cytoskeleton and are necessary for cells to have diverse, complex shapes. They also aid in cell migratory ability. They are made by the centrosome, which contains a pair of cylindrical centrioles at right-angles to each other. Before division, CENPF localises at the end of one of the centrioles (the mother centriole) in order to orient microtubules correctly to form thin cellular projections called cilia. Most cilia are primary cilia, which are involved in cell signalling, sending and receiving signals to trigger cell migration, division or differentiation. Mutations in CENPF disrupt this ability to form cilia; cilia have been found to be fewer in number and shorter when CENPF is mutated. Strømme syndrome therefore falls under the classification of diseases known as ciliopathies. Mutations that have been identified in CENPF have been mostly nonsense mutations, which result in the protein being cut short and usually non-functional as a result, but frameshift and splice-site mutations have also been identified. Several of the nonsense mutations that have led to this syndrome have been in exon 12 of the gene (out of 20), but mutations in other exons have been identified. Severity and symptoms of the syndrome have been variable regardless of the type of mutation but generally consistent within families, suggesting the severity may depend on the presence of mutations in other genes that perform similar functions to or otherwise interact with or affect CENPF (a phenomenon known as epistasis). It has been suggested that an interaction between CENPF and NDE1, which causes microlissencephaly when mutated, is related to the microcephaly in Strømme syndrome. Diagnosis Diagnosis is typically achieved by observation of symptoms; however, genetic testing provides a full confirmation. The microcephaly, intestinal atresia and some of the eye