P705: Diagnosis of galactosialidosis, a rare lysosomal disorder, by combined genome sequencing and biochemical genetic testing

Case Presentation: A couple with an ongoing pregnancy presented to clinic for prenatal genetic counseling because of a significant paternal family history of WAGR syndrome.He reported a sister with Wilms tumor, aniridia, and intellectual disability; a paternal half-brother with Wilms tumor and aniridia deceased from lymphoma; and two paternal uncles who had died in childhood from Wilms tumors.Diagnostic Workup: A karyotype was performed on the proband, and an apparent deletion on 11p13p14 was appreciated.Because the proband was reportedly unaffected and because of his significant family history, we performed a chromosomal microarray and found no abnormality, including in the 11p13p14 region, indicating that the apparent deletion was likely a balanced insertional translocation.Fluorescent in situ hybridization (FISH) was then performed using a probe located between WT1 and PAX6, and we observed presence of this probe on 11p13 and 2q31.With these FISH results, a detailed reanalysis identified a subtle band inserted into the 2q31 region, representing a karyotype of 46,XY,t(2;11)(q31;p13p14).