Figure 2: A child with Klippel-Feil syndrome. Note the opisthotonotic position, low set ears, and micrognathia.
Genetic anomalies: Dominant inheritance with reduced penetrance and variable expression of a defective gene on the long arm of chromosome 8 at locus 22.2. Possible role of PAX1 in the pathogenesis of KFS is object of studies. It has been shown that a PAX1 mutant mouse is characterized by vertebral segmentation defects, reminiscent of the human disorder Klippel-Feil syndrome.
Differential diagnosis: Iniencephaly presents with similar opisthotonos but appears more severe (cervical spina bifida); dyssegmental dysplasia presents with similar vertebral findings but adds short limbs and cephaloceles. It is unclear whether Klippel-Feil syndrome is a discrete entity, or if it is one point on a spectrum of congenital spinal deformities. Only by identifying the link between the genetic etiology and the phenotypic pathological anatomy of the syndrome we'll be able to rationalize the heterogeneity of it.
Prognosis: The complications result from the vertebral fusion and include cord compression syndrome, cervical instability, and motility impairment.
Management: Termination of pregnancy can be offered before viability. Standard prenatal care is not altered when continuation of the pregnancy is chosen. Confirmation of diagnosis after birth is important for genetic counseling.
1: Barbosa V, Maganzini AL, Nieberg LG. Dento-skeletal implications of Klippel-Feil syndrome [a case report]. N Y State Dent J. 2005 Jan; 71(1):48-51.
2: Erol M, Caksen H, Tan O, Atik B, Unal O, Odabas D. Report of a girl with Klippel-feil syndrome and Poland anomaly. Genet Couns. 2004; 15(4):469-72.
3: Dickerman RD, Colle KO, Mittler MA.Intramedullary inflammatory mass dorsal to the Klippel-Feil deformity: error in development or response to an abnormal motion segment? Spinal Cord. 2004 Dec; 42(12):720-2.
4: Tracy MR, Dormans JP, Kusumi K. Klippel-Feil syndrome: clinical features and current understanding of etiology. Clin Orthop Relat Res. 2004 Jul ;( 424):183-90.
5: Paksoy Y, SEker M, Kalkan E. Klippel-Feil syndrome associated with persistent trigeminal artery. Spine. 2004 Apr 23; 29(9):E193-6.
6: McGaughran JM, Oates A, Donnai D, Read AP, Tassabehji M.Mutations in PAX1 may be associated with Klippel-Feil syndrome.Eur J Hum Genet. 2003 Jun; 11(6):468-74.
7. Klippel M, Feil A. The classic: A case of absence of cervical vertebrae with the thoracic cage rising to the base of the cranium (cervical thoracic cage). Clin Orthop. 1975;109:3–88. Tracy MR, Kusumi K. Klippel-Feil Syndrome: Clinical features and current understanding of etiology. Pediatrics 2004;(424):183-190