LTBP4 and cutis laxa: c.4022C>G is implicated in FLNB-Related Spectrum Disorders, Joubert syndrome, Meckel–Gruber syndrome, “Cutis laxa” with severe pulmonary involvement, gastrointestinal and urinary abnormalities, and CC2D2A, PTCH1, LTBP4, and DMD-related disorders, but its significance is uncertain and its pathogenicity has conflicting interpretations.