Diagnosis of a case with partial 9p trisomy by next generation sequencing

Objective: To explore the genetic cause for a child featuring growth and mental retardation. Methods: Following conventional karyotyping analysis of the trio family, next generation sequencing (NGS) was carried out to explore the origin of the supernumerary marker chromosome. Fluorescence in situ hybridization (FISH) was used to confirm the result. Results: The karyotypes of both parents were normal, while the proband was found to be 47, XX, + mar. NGS showed that the supernumerary marker has originated from chromosome 9pl3. 1p24. 3 with a size of 39. 77 Mb. FISH has confirmed the above finding. Conclusion: The 9pl3. l-p24. 3 trisomy probably underlies the abnormal phenotypes of the child. Cytogenetic analysis combined with NGS and FISH can provide accurate diagnosis for such disorders.