We report a male patient with a 46, XY, der (11) t (1; 11) (q31; q25) karyotype due to de novo unbalanced translocation. The boy had facial dysmorphism including prominent wide forehead, short bilateral palpebral fissures, broad nasal bridge, low set and malformed ears, digitalization of thumbs, and small testes. Besides, he also suffered from congenital hydrocephalus and hypogammaglobulinemia, which have not been described in trisomy 1q syndrome. The additional chromatin material on the long arm of chromosome 11 segment was derived from chromosome 1, as proved by high-resolution banding and multiple-color FISH study. This case report allows a further delineation of the trisomy 1q syndrome.