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Limb Developmental Defects

Terms in this set (29)

Acheiria
Absence of one or both hands
Acheiropodia
Absence of hands and feet
Achondroplasia
Retarded growth of long bones resulting in short limb dwarfism
Adactyly
Absence of all digits on a limb
Amelia (ectromelia)
Absence of a limb or limbs
Apodia
Absence of one or both feet
Arachnodactyly
Elongated digits
Brachydactyly
Shortness of digits
Camptodactyly
Flexor deformity in the PIP joint (frequently 5th finger)
Clinodactyly
Curving of a finger medially or laterally, most commonly 5th finger curving towards 4th finger
Hemimelia
Absence of all of part of the distal half of a limb
Meromelia
General term for absence of a part of a limb
Mesomelia
Shortened zeugopod (radius/ulna or tibia/fibula)
Monodactyly
Having a single digit on a hand or foot
Oligodactyly
Presence of less than 5 digits on a hand or foot
Phocomelia
Absence or severe shortening of the proximal part of a limb, with distal parts of limb attached directly to trunk
Polydactyly
Presence of more than 5 digits on a hand or foot: preaxial versus postaxial
Rhizomelia
Shortened stylopod (humerus or femur)
Split hand/foot
Absence of central components of hand/foot
Syndactyly
Fusion of adjacent digits
Talipes equinovarus (clubfoot)
Foot inverted and sole turned medially
Triphalangeal thumb
Thumb with 3 phalanges
Mutation in the Shh pathway and ZRS (ZPA Regulatory sequence)
triphalangeal thumb
extra digit (polydactyly)
Werner mesomelic syndrome (WMS), very severe condition that includes hypoplastic tibia in addition to autopod defects.
polyalanine repeat insertions into the HOXD13 gene
Multiple cases of Type II syndactyly (synpolydactyly - SPD), which is characterized by webbing between fingers as well as partial or complete digit duplication
hypothesized to affect the hand or foot.
Mutations in the FGF receptors (FGF1, FGFR2, and FGFR3)
various skeletal dwarfism and skeletal overgrowth syndromes
autosomal dominant missense mutations in the FGFR3 gene
achondroplasia (skeletal dwarfism) where 97% of cases result from autosomal dominant missense mutations in the FGFR3 gene that cause activation of the FGFR3 that leads to decreased chondrocyte proliferation and differentiation, and increased chondrocyte apoptosis
inactivation of FGFR3
skeletal growth plates have enlarged proliferating and hypertrophic chondrocyte zones which ultimately lead to the syndrome CATSHL (camptodactyly, tall stature, hearing loss).
Amniotic band syndrome
Ttissue bands can encircle various parts of the limbs, severely constricting or even amputating digits or larger segments of limbs.
chorionic villus sampling (CVS),
dilation and curettage, amniocentesis, or severe trauma from a fall or motor vehicle accident can adversely affect the embryo/fetus. likely due to interruption of adequate blood supply to the embryo/fetus.
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