IDC10 Code = E13.9
Genomic coordinate (human 13:27,920,000 PDX1).
Cytoband (human 13q12.2 PDX1).
OMIM’ genes @ 13q12.2 = 6 genes.
ClinVar = 168 PDX1 variants reported.
PANTHER Classification of PDX1 is PTHR45664 “Transcription factor” PC00264.
Swallowtail chromosome-13 is 308 genes. Taylor-4 polynomial series.
Cytoband Structure: WCWCCWG6BGBGB2GB2
⠺ ⠉ ⠺ ⠉ ⠉ ⠺ ⠛⠼⠋ ⠃ ⠛ ⠃ ⠛ ⠃⠼⠃ ⠛ ⠃⠼⠃
Here I present: “Maturity-Onset Diabetes Young-4“, Victor McKusick, Mendelian Inheritance in Man’, 1966. (PDX1)
INTRODUCTION.
The Affected Gene: MODY4 is driven by heterozygous mutations in the PDX1 (Pancreas and Duodenum Homeobox-1) gene located on cytoband 13q12.2. This gene produces a protein vital for early pancreatic development and the healthy function of insulin-producing beta cells.
The ABOVE topology diagram, captures the bifurcation between normal β‑cell function and MODY4 diabetic state as a catastrophe surface governed bywhere α encodes PDX1 transcriptional activity and β represents metabolic‑regulatory input.
In this model: The upper sheet (green) corresponds to stable β‑cell homeostasis maintained by sufficient PDX1 activation.
The lower sheet (red) represents the diabetic attractor basin where haploinsufficiency drives insulin’ transcription collapse.
The cusp point marks the critical threshold — a small perturbation in α or β triggers a discontinuous transition in x, the β‑cell state variable.
This visualization translates genetic dosage sensitivity into catastrophe geometry, showing how MODY4 emerges when the system crosses the cusp boundary.
