Dermal fibroblasts were obtained from patient 8 (3781-3781) by skin punch biopsy and cultured in amnioMAX C-100 complete medium (Life Technologies) as described previously12 (link). RNA was extracted from primary skin-derived fibroblast cell lines from patient 8 (3781-3781) and two sex-matched controls using RNeasy kit (Qiagen) and treated with DNAseI to eliminate genomic DNA, according to manufacturer’s instructions. Complementary DNA (cDNA) synthesis was carried out using random oligomer primers and AMV Reverse Transcriptase (Roche). The cDNA samples were resolved on an E-Gel® electrophoresis system and extracted according to manufacturer’s instructions (ThermoFisher Scientific) in order to sequence the amplicons corresponding to the normal and mutant alleles. Sequences of primers used for cDNA amplification and Sanger sequencing of PUF60 are available upon request.