7-155806509-A-G

Variant names:

• chr7-155806509-A-G
• rs104894040
• NM_000193.4:c.349T>C

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000193.4(SHH):​c.349T>C​(p.Trp117Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. W117G) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: SHH NM_000193.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:3
• Conservation: PhyloP100: 9.08
• Publications: 9 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: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• microphthalmia, isolated, with coloboma 5

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, PanelApp Australia
• polydactyly of a triphalangeal thumb

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

  Inheritance: AD Classification: DEFINITIVE, MODERATE Submitted by: G2P, Ambry Genetics
• 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: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_000193.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr7-155806509-A-C is described in ClinVar as Pathogenic. ClinVar VariationId is 8880.Status of the report is no_assertion_criteria_provided, 0 stars.
• 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 polydactyly of a triphalangeal thumb, microphthalmia, isolated, with coloboma 5, solitary median maxillary central incisor syndrome, holoprosencephaly 3, skeletal system disorder, hypoplastic tibiae-postaxial polydactyly syndrome, holoprosencephaly, syndactyly type 4, microphthalmia, isolated, with coloboma, autosomal dominant preaxial polydactyly-upperback hypertrichosis syndrome, triphalangeal thumb-polysyndactyly syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992
• PP5: Variant 7-155806509-A-G is Pathogenic according to our data. Variant chr7-155806509-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 8881.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SHH	NM_000193.4	c.349T>C	p.Trp117Arg	missense_variant	Exon 2 of 3	ENST00000297261.7	NP_000184.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SHH	ENST00000297261.7	c.349T>C	p.Trp117Arg	missense_variant	Exon 2 of 3	1	NM_000193.4	ENSP00000297261.2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, single submitter

Submissions by phenotype

Holoprosencephaly 3 Pathogenic:3

Nov 22, 2005

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Aug 29, 2013

GeneReviews

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

- -

Feb 27, 2025

Laboratory of Molecular Genetics, CHU Rennes

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The NM_000193.4:c.349T>C, is a missense variant in SHH in the Hedgehog domain (PM1), absent from controls (PM2), predicted pathogenic by prediction tools (PP3). Functional tests showed that SHH signaling activity was abolished (Traiffort et al, J Biol Chem 2004).This variant inherited from the mother is involved in the pathophysiology of holoprosencephaly according to the oligogenic model described in Kim et al (Brain 2019) and is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.47
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	1.0	D;.
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.48
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.99	D;D
M_CAP	Pathogenic	0.80	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.2	M;.
PhyloP100		9.1
PrimateAI	Pathogenic	0.93	D
PROVEAN	Pathogenic	-12	D;D
REVEL	Pathogenic	0.88
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.51	P;D
Vest4		0.97
MutPred		0.98		Gain of disorder (P = 0.0467);.;
MVP		0.97
ClinPred		1.0	D
GERP RS		2.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.95
gMVP		1.0
Mutation Taster		=14/86	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs104894040; hg19: chr7-155599203;