We discuss the genetic abnormality that causes Liebenberg syndrome, the genomic rearrangement at the PITX1 locus on chromosome 5.The structural variations seem to result in an ectopic expression of paired-like homeodomain transcription factor 1 (PITX1) in the forelimb causing a partial arm-to-leg transformation in these patients.
We therefore re-define the phenotype of Liebenberg syndrome as a transformation of the upper limbs to reflect lower limb characteristics and speculate that the area of deletion contains a regulatory sequence that suppresses the expression of PITX1 in the upper limb buds.
We therefore re-define the phenotype of Liebenberg syndrome as a transformation of the upper limbs to reflect lower limb characteristics and speculate that the area of deletion contains a regulatory sequence that suppresses the expression of PITX1 in the upper limb buds.