chr8-38404436-T-C

Variant names:

• chr8-38404436-T-C
• NM_001286819.2:c.1148T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001286819.2(LETM2):​c.1148T>C​(p.Leu383Ser) 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: LETM2 NM_001286819.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.50
• 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: Orphanet, Ambry Genetics, G2P, ClinGen
• hypogonadotropic hypogonadism 2 with or without anosmia

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

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

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

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen
• 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.977

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LETM2	NM_001286819.2	c.1148T>C	p.Leu383Ser	missense_variant	Exon 8 of 11	ENST00000379957.9	NP_001273748.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LETM2	ENST00000379957.9	c.1148T>C	p.Leu383Ser	missense_variant	Exon 8 of 11	5	NM_001286819.2	ENSP00000369291.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Jun 28, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1007T>C (p.L336S) alteration is located in exon 8 (coding exon 6) of the LETM2 gene. This alteration results from a T to C substitution at nucleotide position 1007, causing the leucine (L) at amino acid position 336 to be replaced by a serine (S). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.42	.;T;T;.;.
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.82
FATHMM_MKL	Benign	0.60	D
LIST_S2	Uncertain	0.96	D;D;D;D;D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D
MetaSVM	Uncertain	0.0093	D
MutationAssessor	Pathogenic	3.8	.;.;H;.;.
PhyloP100		7.5
PrimateAI	Uncertain	0.73	T
PROVEAN	Pathogenic	-5.3	D;D;D;D;D
REVEL	Pathogenic	0.80
Sift	Pathogenic	0.0	D;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		1.0	.;D;D;.;.
Vest4		0.93
MutPred		0.89		.;.;Loss of stability (P = 0.0189);.;.;
MVP		0.56
MPC		0.43
ClinPred		1.0	D
GERP RS		5.5
PromoterAI		-0.0028	Neutral
Varity_R		0.87
gMVP		0.86
Mutation Taster		=16/84	disease causing

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

hg19: chr8-38261954;