Exome sequencing identifies a compound heterozygote in C5orf42 gene causing Joubert syndrome in a Chinese family

Purpose: This study is to present the diagnosis of a Chinese Joubert syndrome (JS) patient caused by compound heterozygote mutations in C5orf42 gene. Methods: A 4 months old male child and was admitted to our hospital because of poor head control andcough at least for 10 days. Routine physical examination and auxiliary instrument inspection were undertaken. Whole exome sequencing was performed for the proband. Prioritized candidate genes based on clinics, pedigree, and mutation characters were selected and validated by Sanger sequencing. Functional analysis of JS genes was performed bioinformatics. Results: The proband, who suffered from molar tooth sign, global developmental delay, and cerebellar vermishypoplasia, was diagnosed as JS. Whole exome sequencing identified a compound heterozygote in C5orf42 gene. Further Sanger sequencing confirmed the mutations included c.7570(exon37)delG from the proband’s mother and c.8708-8709(exon46)delAA from his father. Bioinformatics findings suggested that genes caused JS might have a functional network, which is useful for prioritizing new JS genes. Conclusion: We firstly found compound heterozygote mutations in C5orf42 gene that caused JS in Chinese population.