Blended phenotype of TECPR2-associated hereditary sensory-autonomic neuropathy and Temple syndrome.

Uniparental isodisomy (UPiD) can cause mixed phenotypes of imprinting disorders and autosomal-recessive diseases. We present the case of a 3-year-old male with a blended phenotype of TECPR2-related hereditary sensory and autonomic neuropathy (HSAN9) and Temple syndrome (TS14) due to maternal UPiD of chromosome 14, which includes a loss-of-function founder variant in the TECPR2 gene [NM_014844.5: c.1319del, p.Leu440Argfs*19]. This case illustrates challenges associated with a mixed phenotype of ultra-rare disorders and underscores the importance of investigating recessive conditions in homozygosity regions when atypical clinical features occur in patients with well-characterized imprinting disorders.