TMEM16F mutations. (A) TMEM16F mutation screening in the Scott patient under study. Identification of the TMEM16F IVS6 + 1G→A (left) and c.1219insT mutations (right) in the patient's genomic DNA. (B) TMEM16F cDNA analysis. (Top left) Amplification of a TMEM16F cDNA amplicon spanning exons 5-8 yielded only the expected 459-bp fragment in the normal control (lane 1), but also a shorter 345-bp fragment in the patient (lane 2). Lane 3, reverse transcription blank; lane 4, PCR blank; M, molecular weight marker. (Top right) Sequencing of the 345-bp fragment showed that it corresponds to TMEM16F mRNA molecules lacking exon 6 (because of the IVS6 + 1G→A mutation). (Bottom) Schematic representation of the splicing aberration (exon 6 skipping) in the patient's TMEM16F pre-mRNA. (C) Schematic representation of the TMEM16F protein. The positions of the previously described TMEM16F mutation²  (IVS12–1G→T, predicting the truncation of the protein in the third transmembrane domain, shown in yellow) and of the mutations identified in this study (IVS6 + 1G→A, predicting the in-frame deletion of 38 amino acids in the N-terminal cytoplasmic tail, and c.1219insT, predicting the truncation of the protein between the second and third transmembrane domains, both shown in red) are indicated.