8-60801516-CTT-CTTTT

Variant names:

• chr8-60801516-C-CTT
• rs752271550
• NM_017780.4:c.2377-4_2377-3dupTT

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_017780.4(CHD7):​c.2377-4_2377-3dupTT variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000146 in 1,369,362 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000015 (0 hom.)
• Consequence: CHD7 NM_017780.4 splice_acceptor, intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.30
• Publications: 0 publications found

Genes affected

CHD7 (HGNC:20626): (chromodomain helicase DNA binding protein 7) This gene encodes a protein that contains several helicase family domains. Mutations in this gene have been found in some patients with the CHARGE syndrome. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2015]

CHD7 Gene-Disease associations (from GenCC):

• CHARGE syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, PanelApp Australia, Broad Center for Mendelian Genomics, ClinGen, G2P
• hypogonadotropic hypogonadism 5 with or without anosmia

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• hypogonadotropic hypogonadism

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Kallmann syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Omenn syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.0073382254 fraction of the gene. Cryptic splice site detected, with MaxEntScore 12, offset of 0 (no position change), new splice context is: acatgcctttttttttttAGgaa. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHD7	NM_017780.4	c.2377-4_2377-3dupTT		splice_acceptor_variant, intron_variant	Intron 5 of 37	ENST00000423902.7	NP_060250.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHD7	ENST00000423902.7	c.2377-4_2377-3dupTT		splice_acceptor_variant, intron_variant	Intron 5 of 37	5	NM_017780.4	ENSP00000392028.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000146 AC: 2 AN: 1369362 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 677014

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 31258

American (AMR) AF: 0.00 AC: 0 AN: 36016

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 24650

East Asian (EAS) AF: 0.00 AC: 0 AN: 36308

South Asian (SAS) AF: 0.00 AC: 0 AN: 77416

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 49456

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5604

European-Non Finnish (NFE) AF: 0.00000190 AC: 2 AN: 1051726

Other (OTH) AF: 0.00 AC: 0 AN: 56928

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		1.3

Splicing

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

Other links and lift over

dbSNP: rs752271550; hg19: chr8-61714075;