Abbreviated genetic pedigrees are shown for the core members of (A) the index family and (B) the second family identified to be affected by compound-heterozygous mutations in HPCA. For the family in (B), the results of the segregation analysis are shown under each individual: WT, wild-type allele; M1, c.212C>A (p.Thr71Asn) mutation; M2, c.568G>C (Ala190Thr) mutation. The results are consistent with AR inheritance of dystonia due to biallelic mutations in HPCA. Individual II:6 did not report any symptoms suggestive of dystonia; however, this could not be confirmed by examination because he did not live in the UK.