Delayed diagnosis of Townes-Brocks syndrome accompanied with kidney failure

Townes-Brocks syndrome (TBS) is a rare autosomal dominant disorder typically characterized by the triad of anorectal malformations, external ear anomalies and hand malformations such as preaxial polydactyly, caused by mutations in the SALL1 gene. Kidney involvement, although less common, can progress to end-stage kidney failure. Early recognition of the characteristic features, particularly those related to SALL1, is crucial for accurate diagnosis, management, and genetic counseling. Here, we present a Turkish family with TBS in which the diagnosis was delayed due to the absence of the classic triad. The proband exhibited significant developmental delay, kidney failure and a congenital foot abnormality, while other family members showed milder manifestations. A multigene panel revealed a heterozygous variant in SALL1 (NM_002968.3:c.2287dup p.R763Kfs*42), which was also identified in the affected family members presenting with milder phenotypes. This case highlights the broad clinical spectrum of TBS, even within the same family. Because major features may not always be present, it can sometimes be overlooked or misdiagnosed; as in our case, which presents with nearly isolated kidney abnormalities. Our report emphasizes the importance of a comprehensive approach, detailed family history and genetic testing in patients with chronic kidney disease of unknown origin.