Figure 1. The FLNA locus is prone to rearrangement.

(A) The FLNA and EMD genes are flanked by 11.3-kb inverted repeats at Xq28. FLNA encodes for the protein Filamin A, an actin cross-linking protein. EMD encodes for Emerin, a protein disrupted in Emery-Dreifuss muscular dystrophy. Recombination at this locus results in benign inversions. FLNA also lies telomeric to 3 low copy repeats of the color vision gene OPN1 and TEX28. Nonallelic homologous recombination–mediated deletion of OPN1-TEX28 repeats is a known cause of human color blindness. (B) Pedigrees of families 1, 2, and 3. Females are represented by circles, affected individuals by dark circles, and deceased individuals by an angled line. Arrows indicate the proband in each family. (C) Quantitative PCR (qPCR) confirmation of FLNA copy number loss in II-2 and I-2 of family 1. qPCR results targeting sequence centered on chrX:153,240,806. When normalized to a female control, it is apparent that the affected mother and daughter have one copy of the allele at that location, whereas the female control has 2 copies. The father, I-1, has one copy, which is expected for an unaffected male. The 95% confidence intervals were calculated using CopyCaller software by Applied Biosystems.