Effects of Spin4 ablation in aging mice: body composition, bone density, and malignancy prevalence

Many overgrowth syndromes are associated with increased risk of tumorigenesis and malignancies. Our group recently identified a frameshift variant in histone reader SPIN4 located on the X chromosome to be a new genetic cause for human overgrowth. In the current study, we investigated the prevalence of malignancies, along with body weight, body length, body composition and bone mineral density, in Spin4 knockout mice at 18 months of age. We found that male mice lacking Spin4 have increased number of tumors and increased body length, while body weight, body composition and bone mineral density were comparable with wild-type mice. We also analyzed publicly available expression data in various types of human cancers and looked for increased or decreased expression of genes that are implicated in overgrowth syndromes and act through epigenetic mechanisms. We found that the expression of SPIN4, EZH2, and DNMT3A to be elevated in many human cancers compared to the corresponding non-malignant tissue samples. Taken together, our current findings confirm that loss of SPIN4 causes overgrowth in mice (in terms of body length) and is associated with increased prevalence in neoplasia; but does not appear to affect adiposity or bone density.