Genetic Study of the Dilatations of the Idiopathic Bronchi in French Polynesia

Etude génétique Des Dilatations Des Bronches Idiopathiques en Polynésie française

Bronchiectasis, defined by an increase in bronchial caliber and thickening of the bronchial wall, is associated with recurrent respiratory infections, chronic cough and bronchorrhea, and a frequent progression to chronic respiratory failure. Investigator distinguish focal bronchiectasis usually resulting from a localized cause and diffuse bronchiectasis which the possible causes are multiple (immune deficiencies, genetic diseases, auto immune pathologies, aspergillosis broncho -allergic lung, sequelae of pulmonary infections).The etiological assessment is negative in 26 to 53% of cases, defining the idiopathic bronchiectasis. However, the discovery of an underlying cause can change the patient's management (up to 37% of cases).

Despite the lack of epidemiological data in French Polynesia, Australian and New Zealand studies found a high prevalence of bronchiectasis in Polynesians. Few clinical studies published in the early 1980s suggested a ciliary origin.

Due to its geographic characteristics, the Polynesian population constitutes an interesting ethnic group. Indeed, there is a low genetic mixing and the prevalence of certain genetic diseases like the syndrome of Alport or some hereditary retinal dystrophies are high. This type of population is very suitable for discovering new genes in human pathology.

Investigator decided to conduct an observational study to find an underlying genetic cause of bronchiectasis in Polynesians by performing a whole exome sequencing. Investigator chose to study index cases defined by an upset of symptoms during the childhood, a family history of idiopathic bronchiectasis, and/or a consanguinity. Investigator also want to study healthy first degree relatives, in order to be able to better identify the clinical significant of DNA variants and focus the analysis on those that may be pathogenic

*Patients

Inclusion Criteria:

• Polynesian adult more than18 years
• dilatation of idiopathic bronchi confirmed to thoracic CTscan
• Negative etiological balance (including sweat test, research of Dyskinesia Ciliary Primitive and immunological check-up)
• Appearance of symptoms in childhood, or family history of chronic bronchial disease, or notion of inbreeding
• Signed consent
• Affiliated with a social security system

Exclusion Criteria:

• Refusal to participate in the study

  *Relatives

• First-degree healthy relatives

• Polynesian adult more than 18 years

• Signed consent

• Affiliated with a social security system

Exclusion Criteria:

• Refusal to participate in the study