A novel mutation of IFT140 in a preschool child with Mainzer-Saldino syndrome accompanied by rare tumor blastic plasmacytoid dendritic cell neoplasm: a case report

BACKGROUND: Mainzer-Saldino syndrome is a rare autosomal recessive ciliopathy characterized by cone-shaped epiphyses, chronic renal failure, and early-onset severe retinal dystrophy. Blastic plasmacytoid dendritic cell neoplasm is a rare hematologic malignancy. However, the association between these two diseases is unclear, and the coincidence of the two diseases has not been previously reported. CASE PRESENTATION: We report a 5-year-5-month-old Chinese boy who experienced conical epiphysis, retinitis pigmentosa, and distinct cutaneous lesions. Renal ultrasound indicated morphological changes in the kidney. The whole exon sequencing revealed that the proband harbored compound heterozygous variants, including a novel variant c.2471T > C (p.Leu824Pro), a maternally inherited missense variant, and c.1990G > A (p.Glu664Lys) inherited from his father in the IFT140 gene. The proband was clinically and molecularly diagnosed as Mainzer-Saldino syndrome. Meanwhile, the diagnosis as blastic plasmacytoid dendritic cell neoplas (BPDCN) was confirmed by the biopsy of skin mass. CONCLUSION: This is the first case of Mainzer-Saldino syndrome combined with a rare tumor blastic plasmacytoid dendritic-cell neoplasm. Our research expands the mutation spectrum of the IFT140 gene, helping to refine the phenotypic diversity of Mainzer-Saldino syndrome.