Table 2. Quantitative estimates and calculated values in our developmental model of the skin.
| Quantitative values | Explanation | References | |
|---|---|---|---|
| 6 complexes | Average number of rete ridges-dermal papillae complexes per mm skin length | [29] | |
| 0.070 mm | Average height of rete ridges-dermal papillae complexes | [30] | |
| 1.348 mm | DEJ length corresponding to 1 mm of skin length | Calculated in this study | |
| 1.817 mm2 | DEJ surface corresponding to 1 mm2 of skin surface | Calculated in this study | |
| 81.7% | Increase in dermo-epidermal contact due to rete ridges-dermal papillae complexes | Calculated in this study | |
| 10 μm | Diameter of circular base of basal keratinocytes | [31] | |
| 20,000 cells | Number of basal keratinocytes per mm2 skin | Used in this study | |
| 15,000 cells | Number of basal keratinocytes per mm2 skin | [32] | |
| 20,000–30,000 cells | Number of basal keratinocytes per mm2 skin | [33] | |
| 23,146 cells | Number of basal keratinocytes per mm2 skin | Calculated in this study | |
| 1.8 m2 | Average skin surface in adult human body | Used in this study | |
| 3.3x106 mm2 | Average total DEJ surface in adult human body | Calculated in this study | |
| 36x109 cells | Average total number of basal keratinocytes in adult human body | Calculated in this study | |
| (36x109–1) mitoses | Number of mitoses needed to obtain total number of basal keratinocytes | Calculated in this study | |
| 35.1 generations | Number of generations of cells needed to obtain total number of basal keratinocytes | Calculated in this study | |
| 1x10-9 | Approximate per nucleotide point mutation rate per mitosis | [26–28] | |
| 6x109 nucleotides | Approximate number of nucleotides per genome | [34] | |
| 6 mutations | Expected number of novel point mutations per mitosis | Calculated in this study | |
| 216x109 mutations | Expected number of point mutations in basal keratinocytes of human body at adulthood | Calculated in this study | |
| 36x | Average point mutation frequency of each nucleotide in basal keratinocytes of human body at adulthood | Calculated in this study | |
| 105 | Total number of somatic mutations expected to have accumulated per BK at adulthood | Calculated in this study | |
| 6 nucleotides | Number of target nucleotides for a reverse mutation in REB patients with 2 nonsense mutations | Calculated in this study | |
| 6x10-9 | Probability of a reverse point mutation per mitosis | Calculated in this study | |
| 1.6x10-94 | Probability that no reverse mutation occurs during total (36x109–1) mitoses (Pnot) | Calculated in this study | |
| ~1 | Probability that at least one reverse mutation occurs during total number of mitoses (P = 1 –Pnot) | Calculated in this study | |
| 216 mutations | Expected number of reverse point mutations during (36x109–1) mitoses | Calculated in this study | |
| 100 mm2 | Minimal size of revertant patch to be clinically recognizable | [9], Fig 1 | |
| 2x106 cells | Number of basal keratinocytes required for a revertant patch | Calculated in this study | |
| 21 generations | Number of generations needed to obtain 2x106 basal keratinocytes | Calculated in this study | |
| 14th generation | Generation in which revertant cell should occur to obtain revertant patch of 100 mm2 in generation 35 | Calculated in this study | |
| 0.0001 | Probability P that at least one reverse mutation occurs in the first 14 generations | Calculated in this study | |
| 1/10,000 patients | Number of patients predicted to carry clinically recognizable revertant skin patch | Calculated in this study | |
| 1:1,000 | Long term proliferating epidermal stem cells:other basal keratinocytes ratio | [24,35] | |
| 156 | Expected number of reverse mutations in epidermal stem cells during adult life | Calculated in this study | |
DEJ, dermo-epidermal junction; REB, recessive epidermolysis bullosa