[Subtelomeric rearrangements in cryptogenic mental retardation]
A Verdú Pérez1, P L García Murillo, O García Campos
1Unidad de Neurología Pediátrica, Hospital Virgen de la Salud, Toledo, España. averdu@sescam.jccm.es
Introduction:
Mental retardation affects 3% of the population, the origin of which cannot be established in 50% of cases. Subtelomeric rearrangements, not detected by routine cytogenetic studies, might explain some cases of unknown cause.
Patients And Methods:
A study was conducted on 200 subjects with unexplained mental retardations using multiplex ligation dependent probe amplification (MLPA). Abnormal findings were confirmed by fluorescent in situ hybridization (FISH) and/or comparative genomic hybridization technology (CGH-array).
Results:
A subtelomeric aberration was identified in 9 patients. Eight were «de novo»; one was inherited from a phenotypically normal parent. There was a statistically significant association with the presence of more than one dysmorphic feature or with intrauterine growth retardation, but not with the severity of retardation or epilepsy.
Conclusions:
Subtelomeric rearrangements explained 4.5% of cases of mental retardation in our series. The presence of more than one dysmorphic feature or intrauterine uterine growth retardation increases the probability of this type of chromosomal aberration.
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