[Fragile X syndrome. Clinical analysis of 300 Chilean patients with unspecific mental retardation].
BACKGROUND
Fragile X syndrome is the most important cause of sex linked mental retardation and the second of chromosomal origin, after Down syndrome.


OBJECTIVE
To apply the modified Hagerman score to patients with mental retardation and to relate clinical findings with cytogenetic and molecular diagnosis.


METHODS
The modified Hagerman score was applied to 214 male and 86 female patients with mental retardation. The clinical variables in non fragile X and fragile X cases, determined by molecular and cytogenetic methods, were compared.


RESULTS
The score in 210 non fragile X males was 10.5 + 3.7 (range 3-23), compared to 21.4 + 2.1 (range 19 to 23) in the four fragile X patients. All fragile X patients had mental retardation, attention deficits, hyperactivity disorders, hand biting and poor visual contact. Hand biting, flapping and perserving speech were observed in a significantly higher number of fragile X males. Only one of 86 females had fragile X syndrome: Her most relevant findings were a long face and high forehead, an attention deficit, hyperactivity and poor visual contact. No clinical differences with other mentally retarded females were found.


CONCLUSIONS
Approximately 5% of institutionalized males with mental retardation have a fragile X syndrome.
Aspillaga
M
M
Servicio de Genética, Hospital Luis Calvo Mackenna, Antonio Varas, Santiago.
Jara
L
L
Avendaño
I
I
López
M
M
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002677:Chile; D005260:Female; D005600:Fragile X Syndrome / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D008297:Male