A case of SBBYSS syndrome caused by KAT6B gene variant

Objective To analyze the clinical and molecular genetics features of a family affected with Say-Barber-Biesecker-Young-Simpson syndrome (SBBYSS). Methods High-throughput sequencing was used to detect copy number variations (CNVs) and pathogenic variant within the whole exome of the affected child. Results No pathogenic CNV was found in the child, while exome sequencing identified a heterozygous c. 3367_c.3370delAGAA (p.Arg1123Argfs*6) frameshifting variant in the exon 16 of the KAT6B gene. The same variant was not found in either parent. Conclusion The c. 3367_c.3370delAGAA (p.R1123Rfs*6) probably underlies the disease in the affected child. Above finding has facilitated genetic counseling and prenatal diagnosis for the family. Key words: Say-Barber-Biesecker-Young-Simpson syndrome; Developmental delay; KAT6B gene; Genetic variant