ICD10 Code = Q91.7
Swallowtail chromosome-13 is 308 genes.
Here I 🎁 present: “Trisomy-13 Polydactyly”, Victor McKusick, Mendelian Inheritance in Man’, 1966.
INTRODUCTION.
The ABOVE image illustrates a Waddington’s epigenetic landscape modified to show how a genetic disruption leads to an altered developmental outcome.
Key Concepts in the Diagram.
The Landscape: The rolling surface represents the developmental pathways of an organism. As development proceeds, cells and tissues “roll” through valleys that represent stable fates (homeorhesis or chreodes).
Normal Development: The flat blue valley represents a stable, typical pathway leading to normal features, such as hands or feet with the standard number of digits.
Trisomy 13 (Genetic Instability): The presence of an extra chromosome 13 introduces genetic instability, which tilts or alters the topology of the landscape.
Morphogenesis Alteration: This genetic shift forces the developmental trajectory over a “ridge” (indicated by the red arrow) into a completely different valley.
Polydactyly: The new developmental path culminates in an altered physical trait—in this case, polydactyly (the growth of extra fingers or toes), which is a classic congenital feature of Trisomy-13 (Patau syndrome).
