case_images: PMC10965300_01
case_images: PMC10965300_02
case_images: This graph shows areas with loss of homozygosity across the genome of the proband. Heterozygous variants are in black and homozygous variants are in red. Only homozygous variants in red are observed across the entire chromosome 2.
case_images: 10-1055-s-0044-1785442-i2400005-1.jpg
case_images: PMC10965300_02_10-1055-s-0044-1785442-i2400005-1.jpg
case_images: FI2400005-1
case_images:  Whole exome sequencing analysis revealed excessive homozygous rare variants on chromosome 2 ( Fig. 1 ).
case_images: (
  A
  ) SPR variants from the proband, and the parents in the Integrative Genomics Viewer (IGV), demonstrating the proband is homozygous and the mother is heterozygous for the variant and the father does not carry the variant. Variant: SPR:NM_003124:exon3:c.661delG:p.p.Leu222CysfsTer4 (chr2:73118540) [hg19]. The read count of the variant in proband is 172 (homozygous) and is 33 out of 66 in the mother (heterozygous). The father does not carry the variant. (
  B
  ) ZNF142 variants from the proband, and the parents in the IGV, demonstrating the proband is homozygous and the mother is heterozygous for the variant and the father does not carry the variant. Variant: ZNF142:NM_001105537:exon8:c.G2468A:p.Arg823Gln (chr2:219508771) [hg19]. The read count of the variant in proband
  
  
  
  is 268 (homozygous) and is 61 out of 134 in the mother (heterozygous). The father does not carry the variant.
case_images: 10-1055-s-0044-1785442-i2400005-2.jpg
case_images: PMC10965300_02_10-1055-s-0044-1785442-i2400005-2.jpg
case_images: FI2400005-2
case_images: A detailed evaluation of the variants on chromosome 2 confirmed complete isodisomy of chromosome 2 with detection of a homozygous frameshift likely pathogenic variant in SPR (p.Leu222CysfsTer4, chromosome 2p13.2; Fig. 2A ) and a homozygous missense variant of uncertain significance (VUS) in ZNF142 (p.Arg823Gln, chromosome 2q35; Fig. 2B ). Instead both were maternally inherited, compatible with maternal UPD2 in the patient ( Figs. 2A, B ).