NM_000784.4:c.1174G>C

Variant names:

• chr2-218814177-G-C
• NM_000784.4:c.1174G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_000784.4(CYP27A1):​c.1174G>C​(p.Glu392Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,888 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: CYP27A1 NM_000784.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.81

Genes affected

CYP27A1 (HGNC:2605): (cytochrome P450 family 27 subfamily A member 1) This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. This mitochondrial protein oxidizes cholesterol intermediates as part of the bile synthesis pathway. Since the conversion of cholesterol to bile acids is the major route for removing cholesterol from the body, this protein is important for overall cholesterol homeostasis. Mutations in this gene cause cerebrotendinous xanthomatosis, a rare autosomal recessive lipid storage disease. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.992

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CYP27A1	NM_000784.4	c.1174G>C	p.Glu392Gln	missense_variant	Exon 6 of 9	ENST00000258415.9	NP_000775.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CYP27A1	ENST00000258415.9	c.1174G>C	p.Glu392Gln	missense_variant	Exon 6 of 9	1	NM_000784.4	ENSP00000258415.4
CYP27A1	ENST00000494263.5	n.1608G>C		non_coding_transcript_exon_variant	Exon 6 of 7	2
CYP27A1	ENST00000445971.1	n.*635G>C		downstream_gene_variant		5		ENSP00000404945.1
CYP27A1	ENST00000466602.1	n.*86G>C		downstream_gene_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461888 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727244

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cholestanol storage disease Uncertain:1

Oct 17, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 392 of the CYP27A1 protein (p.Glu392Gln). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CYP27A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 2121893). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt CYP27A1 protein function with a positive predictive value of 95%. This variant disrupts the p.Glu392 amino acid residue in CYP27A1. Other variant(s) that disrupt this residue have been observed in individuals with CYP27A1-related conditions (PMID: 19373932, 27455001), which suggests that this may be a clinically significant amino acid residue. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	31
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	H
PrimateAI	Uncertain	0.63	T
PROVEAN	Uncertain	-2.9	D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.94		Gain of MoRF binding (P = 0.0467);
MVP		0.99
MPC		0.71
ClinPred		1.0	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.95

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-219678900;