X-13776244-A-T

Variant names:

• chrX-13776244-A-T
• NM_001001995.3:c.831T>A
• GPM6B p.Ile277Ile

Variant summary

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

The NM_001001995.3(GPM6B):​c.831T>A​(p.Ile277Ile) 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. I277I) has been classified as Benign.

• Frequency: Genomes: not found (cov: 24)
• Consequence: GPM6B NM_001001995.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.242
• Publications: 0 publications found

Genes affected

GPM6B (HGNC:4461): (glycoprotein M6B) This gene encodes a membrane glycoprotein that belongs to the proteolipid protein family. Proteolipid protein family members are expressed in most brain regions and are thought to be involved in cellular housekeeping functions such as membrane trafficking and cell-to-cell communication. This protein may also be involved in osteoblast differentiation. Alternate splicing results in multiple transcript variants. Pseudogenes of this gene are located on chromosomes Y and 22. [provided by RefSeq, Jan 2016]

OFD1 (HGNC:2567): (OFD1 centriole and centriolar satellite protein) This gene is located on the X chromosome and encodes a centrosomal protein. A knockout mouse model has been used to study the effect of mutations in this gene. The mouse gene is also located on the X chromosome, however, unlike the human gene it is not subject to X inactivation. Mutations in this gene are associated with oral-facial-digital syndrome type I and Simpson-Golabi-Behmel syndrome type 2. Many pseudogenes have been identified; a single pseudogene is found on chromosome 5 while as many as fifteen have been found on the Y chromosome. [provided by RefSeq, Aug 2016]

OFD1 Gene-Disease associations (from GenCC):

• Joubert syndrome 10

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• OFD1-related ciliopathy

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• orofaciodigital syndrome I

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae)
• retinitis pigmentosa 23

  Inheritance: XL Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• primary ciliary dyskinesia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• retinitis pigmentosa

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• orofaciodigital syndrome type 6

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• Simpson-Golabi-Behmel syndrome type 2

  Inheritance: XL Classification: LIMITED Submitted by: 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 (REVEL=0.006).
• BP7: Synonymous conserved (PhyloP=0.242 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001001995.3. 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
	GPM6B	NM_001001995.3	MANE Select	c.831T>A	p.Ile277Ile	synonymous	Exon 7 of 8	NP_001001995.1	Q13491-4
	GPM6B	NM_001001996.3		c.831T>A	p.Ile277Ile	synonymous	Exon 7 of 8	NP_001001996.1	Q13491-3
	GPM6B	NM_001318729.2		c.654T>A	p.Ile218Ile	synonymous	Exon 6 of 7	NP_001305658.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GPM6B	ENST00000316715.9	TSL:2 MANE Select	c.831T>A	p.Ile277Ile	synonymous	Exon 7 of 8	ENSP00000316861.4	Q13491-4
	GPM6B	ENST00000355135.6	TSL:1	c.831T>A	p.Ile277Ile	synonymous	Exon 7 of 8	ENSP00000347258.2	Q13491-3
	GPM6B	ENST00000356942.9	TSL:1	c.711T>A	p.Ile237Ile	synonymous	Exon 6 of 7	ENSP00000349420.5	Q13491-1

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 24

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.45
CADD	Benign	12
DANN	Benign	0.80
PhyloP100		0.24

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: chrX-13794363;