PIK3R1 and Telangiectasia: Next-generation sequencing revealed mutations in the ataxia telangiectasia-mutated (<i>ATM</i>), SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily b-member 1 (<i>SMARCB1)</i>, and phosphoinositide-3-kinase regulatory subunit 1 (<i>PIK3R1</i>) genes.