17-1270787-GC-AT

Variant names:

• chr17-1270787-GC-AT
• NM_001164405.2:c.224_225delGCinsAT
• BHLHA9 p.Arg75His

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM5 PP3

The NM_001164405.2(BHLHA9):​c.224_225delGCinsAT​(p.Arg75His) 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 variant affecting the same amino acid position, but resulting in a different missense (i.e. R75L) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: BHLHA9 NM_001164405.2 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.98
• Publications: 0 publications found

Genes affected

BHLHA9 (HGNC:35126): (basic helix-loop-helix family member a9) This gene is a member of the basic helix-loop-helix family. The encoded protein is a transcription factor involved in limb development. Mutations in this gene have been associated with mesoaxial synostotic syndactyly Malik-Percin type (MSSD). Copy number variation of a locus containing this gene has been linked to a form of split-hand/foot malformation with long bone deficiency (SHFLD3). [provided by RefSeq, Mar 2015]

BHLHA9 Gene-Disease associations (from GenCC):

• mesoaxial synostotic syndactyly with phalangeal reduction

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• tibial aplasia-ectrodactyly syndrome

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
• Camptosynpolydactyly, complex

  Inheritance: AR Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
• split-hand/foot malformation with long bone deficiency 1

  Inheritance: Unknown Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_001164405.2
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-1270787-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 162067.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: No computational evidence supports a deleterious effect, but strongly conserved according to phyloP

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001164405.2. 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
	BHLHA9	NM_001164405.2	MANE Select	c.224_225delGCinsAT	p.Arg75His	missense	N/A	NP_001157877.1	Q7RTU4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	BHLHA9	ENST00000391429.2	TSL:6 MANE Select	c.224_225delGCinsAT	p.Arg75His	missense	N/A	ENSP00000375248.1	Q7RTU4

Frequencies

GnomAD3 genomes Cov.: 33

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

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		8.0

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: chr17-1174081;