intracranial hypotension [DOID:4723]
A brain disease that is characterized by low pressure inside the skull, and thus in the brain tissue and cerebrospinal fluid; may occur as a result of an occult or iatrogenically caused leak of CSF into another body cavity; may result in the downward displacement of the cerebellar tonsils through the foramen magnum or Chiari malformation; has_symptom orthostatic headache; other symptoms are related to compression of cranial nerves due to brain sagging.
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.