How common is Klippel-Feil syndrome?
Klippel-Feil Syndrome (KFS) is considered to be a rare condition, but there are people from all different backgrounds and ethnicities living with KFS around the world. The exact incidence of the condition is unknown, although reports estimate that the condition occurs in approximately one in 42,000-50,000 live births. It is likely that many individuals with KFS are living undiagnosed. To support this, a 2018 CT imaging study in a New York hospital emergency unit found the prevalence of KFS in their population to be 1 in 172 with most of the fusions of cervical vertebrae at C5-C6 and C2-C3 levels. Interestingly, KFS is found more frequently in women than men.
Klippel-Feil Syndrome, NORD, https://rarediseases.org/rare-diseases/klippel-feil-syndrome/
Gruber et al, The Prevalence of Klippel-Feil Syndrome: A Computed Tomography-Based Analysis of 2,917 Patients. Spine Deform. 2018 Jul - Aug;6(4):448-453. doi: 10.1016/j.jspd.2017.12.002. https://www.ncbi.nlm.nih.gov/pubmed/29886918
Kippel-Feil. Genetic Disorder UK. http://www.geneticdisordersuk.org/gduknetwork/klippel-feilsyndrome