What is Klippel-Feil syndrome?
Klippel-Feil syndrome (KFS) is a rare medical condition in which at least two of the seven neck bones in the upper spine (cervical vertebrae) are fused together. Other key features of KFS include a short neck, limited neck movement, and a low hairline on the back of the head. Having said this, the specific health problems present in KFS often are different from one individual to another and all of the symptoms may not occur in one person. KFS is a whole body (systemic) condition, accordingly, people living with KFS often have other medical issues. These issues may include; differences in kidney, uterine, and heart formation, chronic nerve and musculoskeletal pain, head pain (both headaches and musculoskeletal),painful involuntary tensing of the neck muscles (cervical dystonia), webbing between fingers and toes (syndactyly), and other bony changes such as missing or fused ribs, cervical ribs, unusually formed bones throughout the body including in the head, face, legs, knees, arms, shoulder blades at different levels (Sprengel's deformity), and multiple spinal changes. Changes in the spine may include; abnormal spinal curvature (scoliosis), narrowing of the spinal canal (spinal stenosis), and the inability of the spinal column (vertebrae) to maintain its standard shape and function during daily activities due extra flexibility at unfused levels of the spine (hypermobility) and the unusual load or weight on it, or abnormal movement of vertebrae (vertebral instability).
KFS can be caused by a new gene change, a gene change inherited from one or both parents, or as a bone formation issue that does not run in the family. Doctors have grouped KFS into different forms based on symptoms and pattern of inheritance (or not); however, some individuals with KFS don't fit exactly into one of the groups.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/klippel-feil-syndrome-109938/overview/66919 • DATE UPDATED: 2019-07-26
Klippel-Feil Syndrome, NORD, https://rarediseases.org/rare-diseases/klippel-feil-syndrome/
"Isolated Klippel-Feil syndrome" Orphanet, https://www.orpha.net/consor/cg,i-bin/OC_Exp.php?Lng=GB&Expert=2345