Compound Heterozygosity of PTF1A Exonic and Enhancer Variants in a Japanese Boy With Pancreatic Hypoplasia

A Japanese boy carried a paternally inherited single‐nucleotide deletion in PTF1A exon 1 (c.775delC) and a maternally inherited nucleotide substitution in the distal enhancer region (g.23508356T>G). Both variants were hitherto unreported. The patient exhibited transient anemia in addition to typical clinical features of pancreatic hypoplasia, but no neurodevelopmental abnormalities. These results highlight the clinical importance and broad mutation spectrum of PTF1A variants as a cause of pancreatic hypoplasia. In addition, our data imply that phenotypes of PTF1A abnormalities are variable and include etiology‐unknown transient anemia.