Characterization of an UNC13D inversion. (A) Nine different primer pairs were used for amplification of overlapping, consecutive UNC13D cDNA fragments. The amplified fragments from a patient (representative of 3 analyzed patients) and a healthy control were separated by gel electrophoresis and are shown relative to their position in the UNC13D transcript. (B) Schematic illustration of a 253-kb inversion identified in patients with FHL. The breakpoints are located in Alu elements containing an identical sequence of 25 bp. Two elements, AluSc8 and AluSx1 (yellow, orange), are located on the reverse strand in intron 30 UNC13D, and an AluY (red) element is located 253 kb upstream of UNC13D on the forward strand. (C) PBMCs from patient O, patient L, and healthy controls were lysed, and protein content was analyzed by SDS-PAGE and Western blotting. Rabbit polyclonal antibodies for detection of Munc13-4 and ERK1 and 2 were used.