Nonmosaic partial duplication 12p

Abstract

We report on a male patient with de-novo pure partial trisomy 12p syndrome besides Robertsonian translocation. The patient had characteristic dysmorphic features such as low-set ear, a high forehead, flat occiput, long philtrum, and nystagmus. He also suffers from intellectual disabilities, seizures, hypotonia, and developmental delay. He has normal anthropometric measurements, and normal height, weight, and skull circumference. A cytogenetic study using the G-banding technique showed 45,XY, add (12)(p12.3), t(13;14)(q10q10). Karyotyping of the parents was performed, which indicated a normal result for the father and 45, XX, t(13;14)(q10;q10) for the mother. The fluorescence in-situ hybridization technique was performed for the patient using whole-chromosome paint 12 and subs telomere 12p. It showed that the add segment on chromosome 12p was derived from chromosome 12 and that 12p subtelomere was inverted and duplicated. Thus, the karyotype is 45, XY, dup (12)(p ter-p12.3), t(13;14)(q10q10). Comparison of the clinical and the cytogenetic findings of our patient with previously reported dup (12p) in the literature was carried out for better characterization and understanding of the phenotypic and cytogenetic relationship.