Genetic analyses of three families with ASD and SHANK3 mutations, (a) In family ASD 1, the proband carries a de novo terminal deletion of the paternal chromosome 22q13. The deletion breakpoint is located in intron 8 of SHANK3. The breakpoint was sequenced after amplification of the proband DNA using primer 1 in SHANK3 and primer 2 in the telomeric repeats. The heterogenous smear in the proband is likely due to the difference in telomere length from chromosome to chromosome and/or priming at different locations by the telomeric primer, (b) In family ASD 2, the two probands carry the same de novo SHANK3 frame-shift mutation on the maternal chromosome 22q13. The mutation is absent from the mother blood and buccal cells, suggesting a germinal mosaicism. The guanine insertion is located in exon 21 of SHANK3, leading to a premature truncated protein, (c) In family ASD 3, the father carries a balanced translocation t(14,22)(p11.2;q13.33), proband A (Asperger syndrome) presents a partial 22qter trisomy and proband B (autism) has a 22qter deletion, (d) Using quantitative fluorescent PCR, we mapped the breakpoint between the genes ALG12 and MLC1. The dosage quotient has a theoretical value of 0.5 for a deletion and 1.5 for a duplication.