Analysis of a pedigree with partial trisomy 9 and partial monosomy 13 derived from a maternal balanced t(9; 13) translocation

Objective To determine the nature and origin of aberrant chromosomes in a child with multiple anomalies and psychomotor retardation. Methods Routine G-banding was carried out to analyze the karyotypes of the patient and his parents, and CNV-seq was used for the fine mapping of the aberrant chromosomal regions. Results The proband and his uncle exhibited psychomotor retardation, craniofacial malformation, infantile external genitalia, and concealed penis. Cytogenetic analysis indicated that the child has a 46, XYqh+ , + (9), t(9; 13)(q13; q12), pat, -13 karyotype. His uncle was XYqh+ , + (9), t(9; 13)(q13; q12)mat, -13, his father was 46, XYqh+ , t(9; 13) (q13; q12)mat, his grandmother was 46, XX, t(9; 13)(q13; q12), and his grandfather was 46, XYqh+ . The result of CNV-seq test for the child was 46, XY, + 9p(pter-p13.2, -40 Mb×3). No deletion was detected. Conclusion The partial trisomy 9 and partial monosomy 13 probably underlie the phenotypic abnormalities in the child. Combined chromosomal karyotyping and DNA sequencing can facilitate delineation of the nature and origin of the aberrant chromosomes. Key words: Partial trisomy 9; Partial monosomy 13; Psychomotor retardation; Infantile external genitalia