Embryology limb defects

embyology guide

1. EMBRYOLOGY TOPIC: LIMB DEFECTS

2. Congenital Limb Deformities: Congenital limb deformities are birth defects in which a fetus’s limbs do not form properly while in uterus Following are the possibilities A baby may be have missing limbs A baby may be have extra limb Over growth of limb Under growth of limb fingers or toes may fail to separate

3. MEROMELIA : Partial absent on limb AMELIA: Complete absence of a limb

4. PHOCOMELIA : Long bones are absent Hand or feet attached to trunk MICROMElIA : all limbs are present but abnormally short

5. BRACHYDACTYLY: Short digits of hand and foot SYNDACTYLY Fused fingers and toes

6. POLYDACTYLY: The presence of extra finger or toe ECTRODACTYLY: Absence of digits

7. CLEFT HAND AND FOOT Consist of a cleft between 2 nd and 4th Metacarpal bone 3 rd metacarpal is absent Thumb, index finger ,4 th and 5 th finger is fused CAUSES : Mutation in the HOXD13 gene results in hand – foot –genital syndrome

8. HOLT –ORAM SYNDROME: Upper limb abnormalities heart defects Absent digits Absent radius Hypoplasia Polydactyly Syndactyly CAUSES: mutation in TBX5 gene

9. OSTEOGENESIS IMPERFECTA: Shortening ,bowing and hypomineralization Of long bones It can cause fractures Causes: Mutation in COL1A1 OR COL1A2 gene that form type 1 collagen

10. MARFAN SYNDROME : Individuals are long slender Long thin limbs Long thin face CAUSES: Mutation in fibrillin CLUB FOOT : Foot pointed downward Foot is rotated toward the other foot Cause : mutation of PITX1 gene

11. CONGENITAL ABSENCE OF RADIUS : Radius is absent CRANIOSYNOSTOSIS RADIAL APLASIA SYNDROME : ( Beller Gerold syndrome) They have stenosis of one or more Cranial sutures Absence of radius

12. TRANSVERSE LIMB DEFICIENCIES : Proximal structures are intact Structures distal to transverse plane are Partially or completely absent CAUSES : Vascular thrombosis Vasoconstriction CONGENITAL HIP DISLOCATION : Under development of acetabulum And h ead of femur Common in female newborns Occur after birth