Partial Trisomy 1q Syndrome: Report of a Case
Partial trisomy 1q is a rare cytogenetic aberration. Transmission to the offsprings of aberrant chromosomes which take part in reciprocal translocations contribute less to the understanding of phenotype/karyotype correlation since aneusomy of both chromosomes contribute to the phenotype. In patients with pure partial duplications due to de novo direct duplications or unbalanced segregation of chromosomes in parental Robertsonian translocations, specific pattern of phenotypic findings caused by the partial trisomy could be understood better. Clinical and cytogenetic findings in a male infant with pure partial trisomy 1q are presented. He had the aberration as a result of transmission of the aberrant chromosome from his mother carrying a balanced Robertsonian translocation between chromosomes 1 and 18. The patient had a long face with a long and flat philtrum, micrognathia with glossoptosis and a high palate, narrow palpebral fissures, hypertelorism with a wide and flat nasal bridge, bilateral overfolded upper helices, long fingers and toes. Cranial MRI revealed hypoplasia of cerebeller hemispheres and periventricular hypomyelination. Echocardiography revealed patent ductus arteriosus and patent foramen ovale which disappeared later. Ophthalmologic examination was normal. On examination of maternal translocation and a series of FISH experiments, the karyotype of the patient was characterised as 46,XY, der(18) t(1;18) (q32;q23) and partial trisomy 1q syndrome was diagnosed. Phenotypic features of patients with pure partial trisomy 1q involving this region are presented.