TUBB2B and tubulinopathy: Moreover, a separate TUBB6 missense variant was reported in a 5-generation syndromic ptosis pedigree (MIM617732).23 Similarly, we identified a TUBA4A heterozygous p.(Arg390His) variant in isolated sporadic ptosis pedigree ENG_IM; this residue aligns with tubulinopathy-associated residues in four paralogs (TUBA1A, TUBB2A, TUBB2B, and TUBB3; ClinVar Variation IDs: 488628, 423490, 418531, 450183, 1214258, 160177, 1203166, 429413, 1320230, 219257).