RESUMO
AIM: We present a mentally retarded boy with partial trisomy of the short arm of chromosome 6 as a result of an interstitial tandem duplication of 6p12.2-p21.31 and immunodeficiency. Patients with mental retardation because of a chromosomal disorder or eponymous syndrome often experience recurrent respiratory tract infections as a result of their associated anatomical or neurological abnormalities. However, associated immune defects may also significantly contribute to their susceptibility to infections. Timely recognition and appropriate treatment of their immunodeficiency will greatly improve quality of life in these patients. CONCLUSION: Immunodeficiency may be the direct cause of recurrent respiratory tract infections in patients with mental retardation because of a chromosomal disorder or eponymous syndrome, even in the face of feeding difficulties and multiple episodes of aspiration, as is illustrated in this boy with partial trisomy 6p.