PURPOSE: Partial trisomy 1q42-qter is a rare chromosomal aberration. Most cases arise from de novo unbalanced translocations or from unbalanced inheritance of parental balanced rearrangements. METHODS: Descriptive case report. RESULTS: A 4-year-old boy had shown an increased neck translucency at the fetal ultrasound examination performed at the 11th week of gestation. Amniocentesis, performed at the 18th week of gestation, did not demonstrate any genetic abnormality. A second fetal ultrasound examination, carried out at the 35th week of gestation, showed congenital clubfeet and hydrocephalus. At birth, clinical examination revealed congenital bilateral ventriculomegaly, bilateral congenital equinovarus clubfeet, low-set ears, plagiocephaly, micrognathia, hypertelorism, prominent forehead, broad nasal bridge, hypertonic syndrome, and inguinal hernia. Ophthalmologic consultation showed the presence of optic pit in his left eye. Genetic counseling was performed. Chromosome analysis demonstrated a partial trisomy 1q42.2-qter associated with a partial monosomy 6q27-qter. Moreover, deletions of the distal region on the long arm of chromosome 6 are frequently associated with both ocular abnormalities and several solid tumor types. Moderate mental and psychomotor retardation has occurred. CONCLUSIONS: This case emphasizes the importance of scheduling a screening test for eye diseases and tumor in these patients.