Retrospective karyotype study in mentally retarded patients.
OBJECTIVE
To describe the chromosomal alterations in patients with mental retardation (MR) using G-banding karyotype analysis.


METHODS
A retrospective study of the results G-banding karyotype analysis of 369 patients investigated for MR was performed. Based on the structural rearrangements found, the authors searched all chromosomal regions related with breakpoints, and these were compared with the literature on MR and databases.


RESULTS
338 (91.6%) normal cases, and 31 (8.4%) with some type of chromosomal abnormality were identified. Among the altered cases, 21 patients (67.8%) were identified with structural chromosomal alterations, nine (29%) with numerical alterations, and one (3.2%) with numerical and structural alterations.


CONCLUSIONS
Structural chromosomal abnormalities were observed more frequently in this study. G-banding karyotyping contributes to the investigation of the causes of MR, showing that this technique can be useful for initial screening of patients. However, higher resolution techniques such as array based comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MPLA) can detect submicroscopic alterations commonly associated with MR.
Instituto Hermes Pardini, Laboratory Specialist, Belo Horizonte MG , Brazil, MSc in General and Applied Biology - Laboratory Specialist at Instituto Hermes Pardini, Belo Horizonte, MG, Brazil.
Wellcy Gonçalves
WG
Teixeira
Instituto Hermes Pardini, Belo Horizonte MG , Brazil, MSc in Genetics - Researcher at Instituto Hermes Pardini, Belo Horizonte, MG, Brazil.
Fabiana Kalina
FK
Marques
Instituto Hermes Pardini, Belo Horizonte MG , Brazil, PhD in Genetics - Researcher at Instituto Hermes Pardini, Belo Horizonte, MG, Brazil.
Maíra Cristina Menezes
MC
Freire
D002869:Chromosome Aberrations; D056905:Chromosome Breakpoints; D025063:Chromosome Disorders; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D059785:Karyotype; D007621:Karyotyping / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D013577:Syndrome
D005819:Genetic Markers