9-114196009-A-C

Variant names:

• chr9-114196009-A-C
• NM_032888.4:c.2121A>C
• COL27A1 p.Arg707Arg

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_032888.4(COL27A1):​c.2121A>C​(p.Arg707Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R707R) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL27A1 NM_032888.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.205
• Publications: 0 publications found

Genes affected

COL27A1 (HGNC:22986): (collagen type XXVII alpha 1 chain) This gene encodes a member of the fibrillar collagen family, and plays a role during the calcification of cartilage and the transition of cartilage to bone. The encoded protein product is a preproprotein. It includes an N-terminal signal peptide, which is followed by an N-terminal propetide, mature peptide and a C-terminal propeptide. The N-terminal propeptide contains thrombospondin N-terminal-like and laminin G-like domains. The mature peptide is a major triple-helical region. The C-terminal propeptide, also known as COLFI domain, plays crucial roles in tissue growth and repair. Mutations in this gene cause Steel syndrome. Alternatively spliced transcript variants have been found, but the full-length nature of some variants has not been determined. [provided by RefSeq, Sep 2014]

COL27A1 Gene-Disease associations (from GenCC):

• Steel syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.54).
• BP7: Synonymous conserved (PhyloP=0.205 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_032888.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL27A1	NM_032888.4	MANE Select	c.2121A>C	p.Arg707Arg	synonymous	Exon 7 of 61	NP_116277.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL27A1	ENST00000356083.8	TSL:1 MANE Select	c.2121A>C	p.Arg707Arg	synonymous	Exon 7 of 61	ENSP00000348385.3	Q8IZC6-1
	COL27A1	ENST00000451716.5	TSL:1	c.1908A>C	p.Arg636Arg	synonymous	Exon 4 of 8	ENSP00000391328.1	Q5T1U7
	COL27A1	ENST00000494090.6	TSL:1	n.1014A>C		non_coding_transcript_exon	Exon 4 of 58	ENSP00000432928.1	H0YD40

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.54
CADD	Benign	8.7
DANN	Benign	0.70
PhyloP100		0.20
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chr9-116958289;