Cytogenetic and molecular profi le of genetic diseases in Puerto Montt main hospital

Background: Chromosome aberrations (CA) are the main etiology of multiple congenital malformations, recurrent abortions and intellectual disability (ID) specifi cally of moderate and severe degree. They account for 0.3 to 1% of newborns (NB) and 6 of 10,000 NB have chromosome imbalances with submicroscopic deletions or duplications smaller than 10 MB that are overlooked by conventional cytogenetic studies. Aim: To report the results of cytogenetic and molecular studies performed in patients with a congenital malformation disease or ID with or without dysmorphic features, attended in a regional hospital. Patients and Methods: One hundred and eighty patients, 27 with a clinical diagnosis of Down syndrome, derived for the suspicion of a genetic disease, were studied. A karyogram was performed in all of them and in 30 cases additional molecular studies, such as fl uorescence in situ hybridization (FISH) or polymerase chain reaction (PCR) were carried out. Results: Among the 153 patients without Down syndrome, 20 (13%) had a genetic abnormality responsible for the altered phenotype. Sixteen had a chromosome aberration (structural and numerical aberrations in 75 and 25% respectively) and four had genetic molecular alterations. Additional studies were performed to confi rm or better characterize the chromosome aberration in 13 of the 30 patients in whom these were requested. Conclusions: Chromosome and specifi c genetic molecular studies in selected cases help to characterize patients with genetic diseases. The collaboration between academic and health care facilities is crucial