rs768071555
Variant summary
Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1PM2BP4_Strong
The NM_017613.4(DONSON):āc.82A>Cā(p.Ser28Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000905 in 1,252,790 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S28I) has been classified as Uncertain significance.
Frequency
Consequence
NM_017613.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 0 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
DONSON | NM_017613.4 | c.82A>C | p.Ser28Arg | missense_variant | 1/10 | ENST00000303071.10 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
DONSON | ENST00000303071.10 | c.82A>C | p.Ser28Arg | missense_variant | 1/10 | 1 | NM_017613.4 | P1 |
Frequencies
GnomAD3 genomes ? AF: 0.000929 AC: 141AN: 151768Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.00171 AC: 4AN: 2340Hom.: 0 AF XY: 0.00140 AC XY: 2AN XY: 1426
GnomAD4 exome AF: 0.000903 AC: 994AN: 1100914Hom.: 1 Cov.: 31 AF XY: 0.000963 AC XY: 505AN XY: 524226
GnomAD4 genome ? AF: 0.000922 AC: 140AN: 151876Hom.: 0 Cov.: 33 AF XY: 0.000889 AC XY: 66AN XY: 74246
ClinVar
Submissions by phenotype
not provided Uncertain:2
Uncertain significance, criteria provided, single submitter | clinical testing | CeGaT Center for Human Genetics Tuebingen | Apr 01, 2022 | DONSON: PM2:Supporting, BS3:Supporting - |
Uncertain significance, criteria provided, single submitter | clinical testing | Invitae | Oct 13, 2022 | This sequence change replaces serine, which is neutral and polar, with arginine, which is basic and polar, at codon 28 of the DONSON protein (p.Ser28Arg). This variant is present in population databases (rs768071555, gnomAD 0.8%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with microcephalic dwarfism (PMID: 28191891). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 431446). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt DONSON protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. - |
Inborn genetic diseases Pathogenic:1
Pathogenic, criteria provided, single submitter | clinical testing | Ambry Genetics | Sep 08, 2021 | The c.82A>C (p.S28R) alteration is located in exon 1 (coding exon 1) of the DONSON gene. This alteration results from an A to C substitution at nucleotide position 82, causing the serine (S) at amino acid position 28 to be replaced by an arginine (R). The c.1466A>C (p.K489T) alteration is located in exon 9 (coding exon 9) of the DONSON gene. This alteration results from an A to C substitution at nucleotide position 1466, causing the lysine (K) at amino acid position 489 to be replaced by a threonine (T). The p.S28R and p.K489T alterations have been observed to be linked in cis and form a haplotype which also includes an intronic c.786-33A>G change (Reynolds, 2017). Based on the available evidence, the DONSON c.[82A>C;1466A>C] (p.[S28R;K489T]) haplotype is classified as pathogenic._x000D_ _x000D_ VUS if seen without c.1466A>C Based on data from gnomAD, the C allele has an overall frequency of 0.08% (25/33238) total alleles studied. The highest observed frequency was 0.66% (3/452) of Ashkenazi Jewish alleles. This haplotype including p.S28R, p.K489T, and c.786-33A>G was detected in the heterozygous state in trans with truncating variants in five unrelated patients with microcephalic dwarfism (Reynolds, 2017). The p.S28R and p.K489T variants were both identified in the homozygous state in an individual from a consanguineous family with spondylo-epi-metaphyseal dysplasia (SEMD) who had many additional homozygous variants in other genes as well (Guo, 2017). The p.S28 and p.K489 amino acids are not well conserved in available vertebrate species. Of the three variants in the common haplotype, only p.K489T was found to have a negative effect in functional studies. The p.S28R alteration failed to reduce protein levels and was able to complement loss of endogenous DONSON during replication fork stalling (Reynolds, 2017). The p.S28R and p.K489T alterations are predicted to be tolerated by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. - |
Microcephaly-micromelia syndrome Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Genomic Research Center, Shahid Beheshti University of Medical Sciences | Mar 05, 2018 | - - |
Microcephaly, short stature, and limb abnormalities Benign:1
Likely benign, criteria provided, single submitter | clinical testing | Victorian Clinical Genetics Services, Murdoch Childrens Research Institute | Mar 31, 2022 | Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Likely benign. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with microcephaly, short stature, and limb abnormalities (MIM#617604) and microcephaly-micromelia syndrome (MIM#251230). (I) 0106 - This gene is associated with autosomal recessive disease. However there has been one previous report of an individual with femoral facial syndrome who was only heterozygous for one DONSON variant (PMID: 31407851). (I) 0200 - Variant is predicted to result in a missense amino acid change from serine to arginine. (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v3) <0.01 for a recessive condition (141 heterozygotes, 0 homozygotes). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v3) (4 heterozygotes, 0 homozygotes). (I) 0503 - Missense variant consistently predicted to be tolerated by multiple in silico tools or not conserved in placental mammals with a minor amino acid change. (SB) 0604 - Variant is not located in an established domain, motif, hotspot or informative constraint region. (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0806 - This variant has moderate previous evidence of being benign in unrelated individuals. This variant has been observed on an ancetral haplotype and in cis with another missense variant p.(Lys489Thr) that is considered pathogenic in at least seven unrelated individuals (ClinVar, PMID: 28191891). This variant has also been classified as pathogenic and as a VUS by clinical laboratories in ClinVar. (SB) 1004 - This variant has moderate functional evidence supporting normal protein function. Western blot and immunoblot studies have shown this variant does not reduce the levels of DONSON protein (PMID: 28191891). This variant has also been shown to rescue spontaneous replication fork stalling observed on DONSON depletion (PMID: 28191891). (SB) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign - |
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at