According to Sutherland (1979), a fragile site has the following characteristics: (1) It is a nonstaining gap of variable width usually involving both chromatids. (2) The site is always at exactly the same point on the chromosome. (3) The site is inherited in a dominant fashion. (4) Fragility must be evident by the production, under appropriate in vitro conditions, of acentric fragments, deleted chromosomes, and triradial figures. Using these criteria, Shabtai et al. (1982) demonstrated a fragile site at 17p12. Izakovic (1984) found homozygosity for fragile site 17p12 in a healthy man.
Izakovic, V. Homozygosity for fragile site at 17p12 in a 28-year-old healthy man. Hum. Genet. 68: 340-341, 1984. [PubMed: 6510913] [Full Text: https://doi.org/10.1007/BF00292597]
Shabtai, F., Klar, D., Halbrecht, I. Chromosome 17 has a real fragile site at p12. (Letter) Hum. Genet. 61: 177-179, 1982. [PubMed: 7129447] [Full Text: https://doi.org/10.1007/BF00274215]
Sutherland, G. R. Heritable fragile sites on human chromosomes. I. Factors affecting expression in lymphocyte culture. Am. J. Hum. Genet. 31: 125-135, 1979. [PubMed: 36752]
Sutherland, G. R. Heritable fragile sites on human chromosomes. II. Distribution, phenotypic effects, and cytogenetics. Am. J. Hum. Genet. 31: 136-148, 1979. [PubMed: 453198]