chr8-38400892-C-A

Variant names:

• chr8-38400892-C-A
• rs188774054
• NM_001286819.2:c.823C>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001286819.2(LETM2):​c.823C>A​(p.Arg275Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. 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. R275C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: LETM2 NM_001286819.2 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0260
• Publications: 0 publications found

Genes affected

LETM2 (HGNC:14648): (leucine zipper and EF-hand containing transmembrane protein 2) Predicted to enable ribosome binding activity. Predicted to be involved in cellular metal ion homeostasis. Predicted to be located in mitochondrial inner membrane. Predicted to be integral component of membrane. [provided by Alliance of Genome Resources, Apr 2022]

FGFR1 (HGNC:3688): (fibroblast growth factor receptor 1) The protein encoded by this gene is a member of the fibroblast growth factor receptor (FGFR) family, where amino acid sequence is highly conserved between members and throughout evolution. FGFR family members differ from one another in their ligand affinities and tissue distribution. A full-length representative protein consists of an extracellular region, composed of three immunoglobulin-like domains, a single hydrophobic membrane-spanning segment and a cytoplasmic tyrosine kinase domain. The extracellular portion of the protein interacts with fibroblast growth factors, setting in motion a cascade of downstream signals, ultimately influencing mitogenesis and differentiation. This particular family member binds both acidic and basic fibroblast growth factors and is involved in limb induction. Mutations in this gene have been associated with Pfeiffer syndrome, Jackson-Weiss syndrome, Antley-Bixler syndrome, osteoglophonic dysplasia, and autosomal dominant Kallmann syndrome 2. Chromosomal aberrations involving this gene are associated with stem cell myeloproliferative disorder and stem cell leukemia lymphoma syndrome. Alternatively spliced variants which encode different protein isoforms have been described; however, not all variants have been fully characterized. [provided by RefSeq, Jul 2008]

FGFR1 Gene-Disease associations (from GenCC):

• encephalocraniocutaneous lipomatosis

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• Hartsfield-Bixler-Demyer syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet, ClinGen
• hypogonadotropic hypogonadism 2 with or without anosmia

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• osteoglophonic dysplasia

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics, Genomics England PanelApp, Orphanet
• Pfeiffer syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• Pfeiffer syndrome type 1

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• Jackson-Weiss syndrome

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• hypogonadotropic hypogonadism

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• isolated trigonocephaly

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

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• septooptic dysplasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• tooth agenesis

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

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

LOC102723716 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14014536).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001286819.2. 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
	LETM2	NM_001286819.2	MANE Select	c.823C>A	p.Arg275Ser	missense	Exon 6 of 11	NP_001273748.1	Q2VYF4-1
	LETM2	NM_001199659.3		c.682C>A	p.Arg228Ser	missense	Exon 6 of 11	NP_001186588.1	Q2VYF4-2
	LETM2	NM_001330515.2		c.679C>A	p.Arg227Ser	missense	Exon 5 of 10	NP_001317444.1	E9PMA4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LETM2	ENST00000379957.9	TSL:5 MANE Select	c.823C>A	p.Arg275Ser	missense	Exon 6 of 11	ENSP00000369291.4	Q2VYF4-1
	LETM2	ENST00000523983.6	TSL:1	c.682C>A	p.Arg228Ser	missense	Exon 6 of 11	ENSP00000428765.2	Q2VYF4-2
	LETM2	ENST00000527710.5	TSL:1	c.181C>A	p.Arg61Ser	missense	Exon 3 of 8	ENSP00000434867.1	Q2VYF4-4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461862 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727234

⚠️ 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: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86244

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000000359436), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.53
CADD	Benign	12
DANN	Benign	0.96
DEOGEN2	Benign	0.064	T
Eigen	Benign	-0.83
Eigen_PC	Benign	-0.85
FATHMM_MKL	Benign	0.15	N
LIST_S2	Uncertain	0.90	D
M_CAP	Benign	0.017	T
MetaRNN	Benign	0.14	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.9	M
PhyloP100		-0.026
PrimateAI	Benign	0.19	T
PROVEAN	Uncertain	-3.4	D
REVEL	Benign	0.026
Sift	Benign	0.061	T
Sift4G	Benign	0.072	T
Polyphen		0.37	B
Vest4		0.25
MutPred		0.49		Loss of MoRF binding (P = 0.0255)
MVP		0.055
MPC		0.081
ClinPred		0.62	D
GERP RS		0.70
Varity_R		0.24
gMVP		0.39
Mutation Taster		=69/31	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs188774054; hg19: chr8-38258410;