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A polydactylous human foot with 'double-dorsal' toes
D D'Souza1, J McDiarmid, C Tickle
1Department of Anatomy and Developmental Biology, University College London, UK.
Journal of Anatomy
|October 3, 1998
Summary
This study examined a 9-toed human foot, revealing abnormal toe development possibly linked to embryonic patterning disruptions. The findings offer insights into polydactyly and limb development.
Area of Science:
- Developmental Biology
- Human Anatomy
- Genetics
Background:
- Polydactyly, the condition of having supernumerary digits, is a common congenital anomaly.
- Understanding the genetic and developmental mechanisms underlying polydactyly is crucial for clinical diagnosis and treatment.
Observation:
- A human polydactylous left foot with nine toes from an 11-month-old child was analyzed using radiographic imaging, MRI, and gross dissection.
- The foot exhibited an unusual toe sequence and morphology, with two dorsally displaced toes displaying characteristics similar to 'double-dorsal' paws in mice.
Findings:
- Morphological examination of tendons and muscles suggested an aberrant toe sequence.
- The two distinct toes possessed duplicated extensor tendons, lacked flexor tendons, and had conical nails at their tips, consistent with a 'double-dorsal' phenotype.
- This phenotype is reminiscent of mouse models with specific gene inactivation during embryonic development.
Implications:
- The findings suggest that disruptions in anteroposterior and dorsoventral patterning during early embryonic limb development may underlie this case of human polydactyly.
- This case provides a potential comparative model for studying limb malformations and the genetic regulation of digit formation in humans and other mammals.