Treacher Collins syndrome 4 [DOID:0080792]
A Treacher Collins syndrome that is characterized by craniofacial dysmorphisms including downslanting palpebral fissures, malar and mandibular hypoplasia, and microtia and that has_material_basis_in heterozygous mutation in the POLR1B gene on chromosome 2q14.
DNA ligase IV deficiency [DOID:0060021]
A combined T cell and B cell immunodeficiency that has_material_basis_in a mutation in the LIG4 gene, a DNA ligase, encoding a protein essential for V(D)J recombination and DNA double-strand break (DSB) repair through nonhomologous end joining (NHEJ). Patients present with immunodeficiency and developmental and growth delay.