tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome is a rare genetic limb malformation syndrome which is characterized by thumb triphalangy, polysyndactyly of the hand and foot, and hypoplasia/aplasia of the tibia bone. additional features include short stature, radio-ulnar synostosis, ectrodactyly and abnormalities of the carpals and metatarsals. only 19 affected families worldwide have been recorded in medical literature. it is associated with a heterozygous base pair substitution of a to g in position 404–406, located on intron 5 in the lmbr1 gene. tibial hemimelia-polysyndactyly-triphalangeal thumb syndromespecialtymedical geneticssymptomsminor physical anomaliescomplicationsgrip, walkingusual onsetpre-nataldurationlife-longcausesautosomal dominant genetic mutationdiagnostic methodphysical examination, radiographypreventionnoneprognosisgoodfrequencyrare, around 20 families worldwide are known to have the disorder to medical literature.