These features were fragile and broke down soon after they were formed.
The specificity of the PWS-like clinical features in fragile X syndrome patients has been debated [ 35].
Brief clinical description: The features of fragile X syndrome include mental retardation and certain characteristic but nonspecific physical features and behaviors.
The best-known features of fragile sites are sequence motifs that are prone to the spontaneous formation of a non-B DNA structure.
(For review of the features of fragile X syndrome, identification of the gene, and its inheritance pattern, see Warren and Sherman (2001) 1 and Hagerman and Hagerman (2002)). 2 The mutation leading to over 98% of cases of fragile X syndrome is an expansion of an unstable CGG repeat sequence located in the 5' untranslated region (UTR) of the FMR1 gene.
The selection was based on the presence of typical neurodevelopmental features of fragile X syndrome including moderate intellectual disability (IQ < 60), autistic and/or stereotypic behavior, and impaired social interaction, associated with at least one of the following physical features: elongated face, macroorchidism, and/or large ears.
Among these, we examined the DNA sequences within and flanking three randomly selected pairs of translocation-prone genes, and found that they exhibit characteristic features of fragile DNA, with frequent AT-rich flexibility islands and the potential of forming highly stable secondary structures.
During childhood, the main clinical signs and features were thin, fragile, but not hyperelastic skin that bruised easily and was particularly thin on the hands and feet; varicose veins; moderate joint laxity; blueish or greyish sclerae; downslanting palpebral fissures; and hypodontia of one or a few teeth in permanent dentition.
The best-known feature of fragile sites is the presence of a sequence motif that is prone to the spontaneous formation of a non-B DNA structure.
Fragility has been recognised as a high probability of extinction or damage of a species, feature, or system and conservation or protection has been seen as a natural consequence for those fragile features (Ratcliffe, 1977; Wright, 1977; see Smith & Theberge, 1986, for review).
