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ABSTRACT
Since DNA structure was described, several studies have been carried out in genetics that promoted a revolution in
the practice of medicine. Human syndromes that were practically undiagnosed became easily diagnosed with
molecular tools. However, most of the genetic diseases remain under diagnostic obscurity, increasing health concerns
for affected people and public demand for preventive health care such as the case of Fragile-X Syndrome, the most
common heritable form of mental retardation in humans. FXS is caused by an expansion of CGG repeat sequence in
the promoter region of FMR1 gene, located in Xq27.3. Both men and women are affected by FXS and pre-mutation
can expand to a full mutation in the next generation. Under full mutation status (200 repeats) the gene is silenced
and FMRP protein is not produced causing mental retardation, speech delay, and behavior problems, the most
frequent symptoms in FXS. Prevalence of FXS is estimated in 1:4000 and 1:8000 and of carriers in the general
population as 1:813 and 1:259 for men and women, respectively. Because of FXS potential to affect subsequent
generations it is crucial to properly diagnose the syndrome. Laboratory analysis of DNA from FXS, using PCR or
Southern Blotting, allows reaching the diagnosis in 99% of cases carrying mutated genes. However, to date the
Brazilian Public Health System does not recognize the molecular methods to reach complete diagnostic in FXS.
Early diagnose would allow fore more appropriate and efficient therapy approaches, favoring satisfactory
development of all affected people, minimizing their suffering and the burden on their families, increasing, on the
other hand, their quality of life which should go beyond survival.
Key words: FXS, mental retardation, SUS, genetic testing
Desde os primórdios, os homens buscaram interpretar a realidade em que viviam
em função da necessidade de sobrevivência. O único conhecimento que vigorava para explicar
os fenômenos que ocorriam na natureza era senso comum que apresentava tendências à
mistificação e coincidia causa e intenção. Era um conhecimento transmitido de geração a geração
por meio de uma educação informal, e baseado em imitação e experiência pessoal, não sendo,
portanto, considerado confiável (Lakatos et al., 1986).
O senso comum era um tipo de conhecimento valorativo, falível, inexato, dado
pela simples observação dos fatos do mundo sensível e em conformação com a aparência. Esse
conhecimento apresentou sua fragilidade na dialética platônica, na medida que Platão, utilizando-
se deste, levou seu interlocutor a descobrir ele próprio à verdade.