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. 2020 Feb 26;11(3):248. doi: 10.3390/genes11030248

Figure 2.

Figure 2

Pedigree of Family 2 with haplotype segregation within the FMR1 locus and CGG sizing through PCR. (A) Black square (III-3) indicates the affected FXS individual, carrying a MFM; grey circles indicate FM carrier females. Individuals tested for the FMR1 expansion are indicated with an asterisk near the symbol. On the left side, the polymorphic markers (CGG, DXS1227, DXS1073, DXS548 and FRAXAC1) are reported. Note that DXS548 and FRAXAC1 were not informative. (B) Capillary electrophoresis of the fluorescent PCR for CGG sizing of the proband’s maternal uncle II-3 (upper panel), of the mother II-1 (middle panel), and of the proband III-2 (lower panel). In each panel, the CGG repeat number was estimated from the size of the PCR products. In III-2, the allele is shorter than the normal range without signs of interspersed AGGs and no sign of mosaicism. On the other hand, II-3 is a mosaic carrier of a small PM of 56 CGGs and a FM while II-1 was eventually found to be a mosaic between a FM and a contracted allele similar to that inherited by her child (III-2). The proband had the reversed allele with the 85 bp deletion followed by 19 CGGs derived from his mother. Bars on the capillary electrophoresis of II-1 indicated the presence of two canonical interspersed AGGs on the normal 29 CGG repeat allele.