It is also important to note that DNAAF1 genotype-phenotype correlations are likely to be unusually broad because heterozygous germline mutations in DNAAF1 (for example, p.Gln307Glu) are associated with an increased risk of testicular germ cell tumours in humans (23,32,33), and rare heterozygous missense mutations are also associated with neural tube defects (33). Here, DNAAF1 is linked to isolated spina bifida.