RESUMO
BACKGROUND: Few patients with interstitial deletions in the distal long arm of chromosome 14 have been reported, and these patients showed rather indistinct features, including growth and mental retardation and phenotypic alterations. RESULTS: We describe a de novo 14q interstitial deletion in a 6-year-old boy with dysmorphic facial traits such as hypertelorism, short and narrow palpebral fissures, broad nose with anteverted nostrils, long philtrum, thin upper lip with cupid's bow, prominent and everted lower lip, mildly low-set ears, as well as moderate developmental delay and mild mental retardation. Array-CGH mapped the deletion to the region 14q24.3 to 14q31.3, including 13.11 Mb, proximal to the imprinted genomic region of 14q32. CONCLUSION: This mild phenotypic presentation suggests that the deleted segment does not contain essential genes for early organ development. Twenty-two genes with known functions, including Neurexin III (NRXN3, OMIM 600567), map to the region deleted in the propositus.
RESUMO
O trabalho apresenta uma analise de fatores causais da sindrome de Down e sua patogenese. Faz tambem uma revisao da historia natural dessa sindrome e dos efeitos da trissomia da banda cormossomica 21q22, considerada critica para o disturbio. Embora esse desequilibrio cromossomico esteja necessariamente presente na sindorme de Down, a relevancia do determinismo genetico e questionada a partir da observacao da possibilidade de desenvolvimento potencial cognitivo em sujeitos afetados pela sindrome, apos a aplicacao de programas de estimulacao neuromotora e psicopedagogicos.