Evidence for a low-penetrant extended phenotype of RTPS1 from a kindred with gain of SMARCB1 exon 6

We report on a long-term survivor of an atypical teratoid/rhabdoid tumor (ATRT-TYR) as an index patient, who carries a SMARCB1 exon 6 gain inherited from his father. The father was diagnosed with an unusual sequence of a myxopapillary INI1-negative ependymoma and a relapsing BRAF V600 wild type hairy-cell leukemia. He has two yet healthy sisters aged 33 and 38 years carrying the same variant, from which one had lost an infant to a malignant brain tumor. This family highlights the existence of RTPS1-associated SMARCB1 germline alterations with reduced penetrance and extends the spectrum of involved diseases