A T cell, B cell, and NK cell deficiency characterized by variably decreased numbers of T cells, lesser deficiencies of B and NK cells, decreased phosphorylation of the extracellular-signal-regulated serine kinase ERK in T and B cells, and onset in early childhood of recurrent bacterial, viral, and fungal infections that has_material_basis_in homozygous or compound heterozygous mutation in the RASGRP1 gene on chromosome 15q14.