Familial Klippel-Feil syndrome and paracentric inversion inv(8)(q22.2q23.3)

Area of Science:

• Genetics
• Developmental Biology
• Orthopedics

Background:

• Klippel-Feil Syndrome (KFS) is a congenital disorder characterized by the fusion of cervical vertebrae.
• KFS is thought to arise from errors in embryonic axis segmentation and is often linked to craniofacial abnormalities.
• The genetic basis of KFS is largely unknown, with suspected heterogeneity.

Purpose of the Study:

• To identify a potential gene locus for familial KFS.
• To investigate the genetic underpinnings of a specific KFS presentation within a multi-generational family.

Main Methods:

• Family-based genetic linkage analysis was performed on a four-generation family (KF2-01) exhibiting KFS.
• Cytogenetic analysis identified a chromosomal inversion, inv(8)(q22.2q23.3), segregating with the disorder.
• Clinical evaluation focused on the pattern of vertebral fusion and associated malformations.

Main Results:

• The first evidence of a familial KFS gene locus on chromosome 8q was established.
• The identified chromosomal inversion, inv(8)(q22.2q23.3), segregated with congenital vertebral fusion in the KF2-01 family.
• Affected individuals presented with a dominant form of KFS, primarily involving cervical spine fusion (C2-3, C4-5, C6-7), laryngeal cartilage malformation, and vocal impairment.

Conclusions:

• A specific locus on chromosome 8q is implicated in familial Klippel-Feil Syndrome.
• The inv(8)(q22.2q23.3) chromosomal abnormality is associated with a dominant form of KFS.
• This finding provides crucial insight into the genetic etiology of KFS, particularly its cervical spine and vocal manifestations.