From roughly 7 years old thereafter, most childrens permanent teeth would have undergone complete development (except their wisdom teeth), and therefore their susceptibility to fluorosis is greatly reduced, or even insignificant, despite the amount of intake of fluoride. The severity of dental fluorosis depends on the amount of fluoride exposure, the age of the child, individual response, weight, degree of physical activity, nutrition, and bone growth. Individual susceptibility to fluorosis is also influenced by genetic factors.Many well-known sources of fluoride may contribute to overexposure including dentifrice/fluoridated mouthrinse (which young children may swallow), excessive ingestion of fluoride toothpaste, bottled waters which are not tested for their fluoride content, inappropriate use of fluoride supplements, ingestion of foods especially imported from other countries, and public water fluoridation. The last of these sources is directly or indirectly responsible for 40% of all fluorosis, but the resulting effect due to water fluoridation is largely and typically aesthetic. Severe cases can be caused by exposure to water that is naturally fluoridated to levels above the recommended levels, or by exposure to other fluoride sources such as brick tea or pollution from high fluoride coal.Dental fluorosis has been growing in the United States concurrent with fluoridation of municipal water supplies, although disproportionately by race. A 2010 CDC report acknowledges an overall incidence of dental fluorosis of 22% from 1986-87 increased to 41% in the early 21st century, with an increase in moderate to severe dental fluorosis from 1% to 4%.
Short-limb skeletal dysplasia with severe combined immunodeficiency is an extremely rare autosomal recessive type of achondroplasia which is characterized by short stature,  bowing of the long bones, and generalized metaphyseal abnormalities alongside signs of SCID such as recurrent severe infections, failure to thrive, chronic diarrhea, and a notable absence of T and B lymphocytes. Around 11 cases have been described in medical literature. == References ==