Guide to Klippel-Feil Syndrome

Klippel-Feil Syndrome is a rare genetic disorder characterized by a fusion of two cervical vertebrae along the spine. Depending on the genetic mutation, the inheritance patterns of the disorder can either be autosomal recessive or dominant . The prevalence rate of the Klippel-Feil syndrome has not yet been determined. Even though the symptoms can be extreme, treatments exist to lessen the severity of the disorder.

Signs and Symptoms

Patients with Klippel-Feil syndrome experience a fusion of any two of the seven cervical vertebrae of the neck. This occurs when normal segmentation and differentiation fails in the neck causing two vertebrae to join together during development in the womb. Direct results of the fusion include a short neck and decreased mobility of the spine. In more extreme cases, some patients might have scoliosis, a curvature of the spine, and spina bifida, a spine defect starting at birth, all due to the abnormal connections in the two vertebrae.

Other symptoms include heart defects, structural abnormalities of the face, skeleton, brain, arms, fingers and spinal cord. Patients also may experience defects in the kidneys, ribs and respiratory system.

Causes

Through the use of genetic pedigree tools, researchers know that a genetic factor for Klippel-Feil syndrome is evident. Using mouse models, it is estimated that a mutation in the PAX gene family might be the cause for the disorder. PAX plays an important role in the production of critical organs and tissue during fetal development. Without this fully effective gene, the fetus lacks the ability to maintain the function of specific cells during and after birth, mainly the spinal cord.

Generally, Klippel-Feil syndrome is an autosomal recessive genetic disorder, meaning that an individual needs two affected PAX genes to get the disorder. This trend is commonly seen in a C5-C6 fusion of the vertebrae. The disorder can also show an autosomal dominant inheritance pattern. The pattern differs in that a patient needs only one mutated PAX gene to be affected with Klippel-Feil syndrome. This is seen more commonly in patients with a fused C2-C3 vertebrae.

Diagnosis and Treatment

Diagnosis of Klippel-Feil syndrome can occur in multiple ways. At birth, doctors may visibly notice the fusion by the curvature of the spine or the lack of mobility of the neck. If not, the symptoms will be noticed later in life. The disorder can also be diagnosed through genetic testing and pedigrees. By analyzing and sequencing the PAX genes researchers can see if a mutation in the gene exists. Also, family history might be evaluated by a genetic counselor to determine possible inheritance patterns and other affected individuals in a family line.

A cure of Klippel-Feil syndrome is not yet available, but symptomatic treatment options do exist. Surgeries are performed to increase mobility of the neck, fix the curve of the spine if one exists, and correct scoliosis. Physical and occupational therapists can provide additional support.

References

• https://www.ninds.nih.gov/disorders/klippel _feil/klippel_feil.htm
• https://www.wheelessonline.com/ortho/klippel _feil_syndrome
• https://gait.aidi.udel.edu/educate/klipfeil.htm