Fig. 1: Familial co-segregation analysis demonstrates chromosomal architecture of identified variants. | npj Genomic Medicine

Fig. 1: Familial co-segregation analysis demonstrates chromosomal architecture of identified variants.

From: Familial co-segregation and the emerging role of long-read sequencing to re-classify variants of uncertain significance in inherited retinal diseases

Fig. 1

a Widefield color fundus photographs reveal rare bone spicule lesions in the far nasal periphery which are more prominent on autofluorescence images in a patient with clinical features of Usher syndrome. b Variants can be identified from NGS but the short-read lengths limit the ability of NGS to determine if said variants reside in cis or in trans. Familial co-segregation analysis can demonstrate if variants reside in trans, as in this case, where the two pathogenic variants in USH2A identified in the proband (black filled-in circle) can be traced from her parents who each carry one of the two variants, with the proband’s father harboring the c.6224G>A (p.Trp2075Ter) variant and the proband’s mother harboring the c.4645C>T(p.Arg1549Ter) variant. c In Cases 1–3, the variants in each proband were demonstrated to be in trans with familial co-segregation analysis, whereas in Case 4 the variants were confirmed to arise de novo after familial co-segregation testing. Paternally inherited variants are denoted in red whereas those denoted in green were maternally inherited.

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