[Genetic screening to determine an etiologic diagnosis in children with mental retardation].
BACKGROUND
Mental retardation or intellectual disability affects 2% of the general population, but in 60% to 70% of cases the real cause of this retardation is not known. An early etiologic diagnosis of intellectual disability can lead to opportunities for improved educational interventions, reinforcing weak areas and providing a genetic counseling to the family.


OBJECTIVE
To search genetic diseases underlying intellectual disabilities of children attending a special education school.


METHODS
A clinical geneticist performed the history and physical examination in one hundred and three students aged between 5 and 24 years (51 males). A blood sample was obtained in 92 of them for a genetic screening that included a standard karyotype, fragile X molecular genetic testing and search for inborn errors of metabolism by tandem mass spectrometry.


RESULTS
This approach yielded an etiological diagnosis in as much as 29 patients. Three percent of them had a fragile X syndrome. Inborn errors of metabolism were not detected.


CONCLUSIONS
This type of screening should be done always in children with intellectual disability to establish an etiological diagnosis.
Unidad de Genética y Enfermedades Metabólicas, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile, Chile. malliend@inta.cl
M Angélica
MA
Alliende
Laura
L
Cámpora
Bianca
B
Curotto
Jessica
J
Toro
Alf
A
Valiente
Marcela
M
Castillo
Fanny
F
Cortés
César
C
Trigo
Cecilia
C
Alvarado
Manuel
M
Silva
Margarita
M
Caru
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D020732:Cytogenetic Analysis / Q000379:methods*; D004519:Education, Special; D005260:Female; D005600:Fragile X Syndrome / Q000175:diagnosis / Q000235:genetics; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D007621:Karyotyping; D008297:Male; D009154:Mutation / Q000235:genetics*; D012720:Severity of Illness Index; D055815:Young Adult