PMC6090943_01
Clinical presentation and molecular cytogenetics analysis of the present patient. a Clinical presentation of the patient at 8 months of age. He had minor facial dysmorphic features including a broad, prominent forehead, mildly depressed nasal bridge, thin upper lip, small chin, and boarder-line low set ears. b-d Cytogenetic analysis identified a deletion and an AOH resulted by duplication in chromosome 21. b CGH and SNP array profile of chromosome 21. The numbers in the CGH pane are indicating log2 ratio of the intensity of fluorescence of the patient versus control genome. In the SNP pane, the numbers indicate the number of B allele. c Karyotype of the patient. d FISH analysis in both metaphase and interphase cells using probes designed for testing presence or absence of the 21q22.11q22.3 region (red). e Genotyping by Sanger sequencing indicating the paternal origin of the derivative chromosome 21. SNPs rs2776109 and rs68172960 (shown in red) are located in the 21q11.2q21.3 region, and rs6517210 and rs9968008 (shown in blue) covered the 21q22.11q22.3 UPD region. f Genomic location of the 21q deletions in the present patient and previously published cases. The red bar indicates the 15.98 Mb deletion at 21q11.2q21.3 (chr21:15,143,552_31,118,908, GRCh37/hg19) in our patient. The black bars represent the deletion regions of previously reported cases with isolated deletion at 21q overlapping with our patient, without any other chromosomal structural abnormality. Genomic locations are showed by UCSC genome browser
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Fig1
He had minor facial dysmorphic features including a broad, prominent forehead, mildly depressed nasal bridge, thin upper lip, small chin, and boarder-line low set ears (Fig. 1a). The CGH array detected a 15.98 Mb deletion in the 21q11.2q21.3 chromosome region, arr[GRCh37] 21q11.2q21.3(15143552_31118908)x 1 (Fig. 1b). The SNP array confirmed the deletion and also showed absence of heterozygosity (AOH) at 21q22.11q22.3 with a size of approximately 14.32 Mb (chr21:33,080,313_47,399,375, GRCh37/hg19) (Fig. 1b). Chromosome analysis revealed an abnormal karyotype, 45,XY,-21,der(21)dup(21)(q22.11q22.3) (Fig. 1c), that is a loss of an entire chromosome 21 and duplication of the 21q22.11q22.3 region on the derivative 21. This duplication was subsequently confirmed by FISH showing the two signals on the der(21) (Fig. 1d). G-banding demonstrated a normal karyotype in both parents. Genotyping clearly demonstrated paternal origin of the der(21) (Fig. 1e).