7-155803521-CTC-TTG

Variant names:

• chr7-155803521-CTC-TTG
• NM_000193.4:c.766_768delGAGinsCAA
• SHH p.Glu256Gln

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP2

The NM_000193.4(SHH):​c.766_768delGAGinsCAA​(p.Glu256Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. It is difficult to determine the true allele frequency of this variant because it is of type MNV, and the frequency of such variant types in population databases may be underestimated and unreliable. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E256K) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SHH NM_000193.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.33
• Publications: 0 publications found

Genes affected

SHH (HGNC:10848): (sonic hedgehog signaling molecule) This gene encodes a protein that is instrumental in patterning the early embryo. It has been implicated as the key inductive signal in patterning of the ventral neural tube, the anterior-posterior limb axis, and the ventral somites. Of three human proteins showing sequence and functional similarity to the sonic hedgehog protein of Drosophila, this protein is the most similar. The protein is made as a precursor that is autocatalytically cleaved; the N-terminal portion is soluble and contains the signalling activity while the C-terminal portion is involved in precursor processing. More importantly, the C-terminal product covalently attaches a cholesterol moiety to the N-terminal product, restricting the N-terminal product to the cell surface and preventing it from freely diffusing throughout the developing embryo. Defects in this protein or in its signalling pathway are a cause of holoprosencephaly (HPE), a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres. HPE is manifested by facial deformities. It is also thought that mutations in this gene or in its signalling pathway may be responsible for VACTERL syndrome, which is characterized by vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, radial and renal dysplasia, cardiac anomalies, and limb abnormalities. Additionally, mutations in a long range enhancer located approximately 1 megabase upstream of this gene disrupt limb patterning and can result in preaxial polydactyly. [provided by RefSeq, Jul 2008]

SHH Gene-Disease associations (from GenCC):

• holoprosencephaly 3

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• microphthalmia, isolated, with coloboma 5

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• polydactyly of a triphalangeal thumb

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P
• solitary median maxillary central incisor syndrome

  Inheritance: AD Classification: DEFINITIVE, MODERATE Submitted by: Ambry Genetics, G2P
• skeletal system disorder

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• autosomal dominant preaxial polydactyly-upperback hypertrichosis syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hypoplastic tibiae-postaxial polydactyly syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• microphthalmia, isolated, with coloboma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• syndactyly type 4

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• triphalangeal thumb-polysyndactyly syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• holoprosencephaly

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 26 curated pathogenic missense variants (we use a threshold of 10). The gene has 8 curated benign missense variants. Gene score misZ: 2.9479 (below the threshold of 3.09). Trascript score misZ: 0.49525 (below the threshold of 3.09). GenCC associations: The gene is linked to solitary median maxillary central incisor syndrome, skeletal system disorder, holoprosencephaly, polydactyly of a triphalangeal thumb, syndactyly type 4, holoprosencephaly 3, microphthalmia, isolated, with coloboma 5, hypoplastic tibiae-postaxial polydactyly syndrome, autosomal dominant preaxial polydactyly-upperback hypertrichosis syndrome, triphalangeal thumb-polysyndactyly syndrome, microphthalmia, isolated, with coloboma.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000193.4. 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
	SHH	NM_000193.4	MANE Select	c.766_768delGAGinsCAA	p.Glu256Gln	missense	N/A	NP_000184.1	Q15465
	SHH	NM_001310462.2		c.301+2773_301+2775delGAGinsCAA		intron	N/A	NP_001297391.1
	SHH	NR_132318.2		n.562+2773_562+2775delGAGinsCAA		intron	N/A

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SHH	ENST00000297261.7	TSL:1 MANE Select	c.766_768delGAGinsCAA	p.Glu256Gln	missense	N/A	ENSP00000297261.2	Q15465
	SHH	ENST00000430104.5	TSL:1	c.301+2773_301+2775delGAGinsCAA		intron	N/A	ENSP00000396621.1	C9JC48
	SHH	ENST00000435425.1	TSL:1	n.301+2773_301+2775delGAGinsCAA		intron	N/A	ENSP00000413871.1	F8WEH4

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.3

Splicing

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: chr7-155596215;