A blended phenotype of primary immunodeficiency and Temtamy syndrome: Dual homozygosity for STK4 and C12orf57 gene variants in a Tunisian infant.

We report a 6-month-old male, born to consanguineous parents, presented with recurrent bronchopneumonia, global developmental delay, and craniofacial dysmorphism.

Initial workup revealed profound T-cell lymphopenia and hypoplasia of the splenium of the corpus callosum.

Whole exome sequencing (whole exome sequencing) identified two homozygous pathogenic variants: a mutation in C12orf57 , diagnostic of Temtamy syndrome, and a mutation in STK4 , confirming a primary immunodeficiency.

Investigations confirmed cold agglutinin disease, validating the severe immune dysregulation predicted by the STK4 genotype.