Is MPI p.Phe256= (c.768C>T) pathogenic?

MPI p.Phe256= (c.768C>T) is classified Likely benign in MPI (ClinVar, Single submitter, 1 submitter; last evaluated 2021-06-30). Very rare (popmax 0.00668%, eas); Associated with MPI-congenital disorder of glycosylation.

What condition is associated with MPI p.Phe256= (c.768C>T)?

MPI p.Phe256= (c.768C>T) is associated with MPI-congenital disorder of glycosylation (ClinVar).

How common is MPI p.Phe256= (c.768C>T) in the general population?

MPI p.Phe256= (c.768C>T) is very rare (popmax 0.00668%, eas) (gnomAD).

How is MPI-CDG inherited?

Typically Autosomal recessive (Orphanet). A genetic counselor can assess individual risk for a family.

MPI p.Phe256=

c.768C>T · rs1402063128 · VCV754663

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.00668%, eas)

Conditions

MPI-congenital disorder of glycosylation

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 1.1	GERP -0.76, phastCons 1
Overall
CADD	11.67	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.00668% East Asian · 3/44,900 alleles

Filtering AF 0.00177% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.000891%

Overall 0.000186% 3/1,614,064 alleles · very rare exomes 2/1,461,888 · genomes 1/152,176 · joint denominator

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: MPI
Protein: p.Phe256=
Coding: c.768C>T
MANE Select: NM_002435
dbSNP: rs1402063128
Type: single nucleotide variant
Location: chr15:74896249 (GRCh38)
Gene constraint: LOEUF 1.04 · pLI <0.01 (gnomAD)
Structure: AlphaFold pLDDT 96.50

Full MPI gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

MPI-congenital disorder of glycosylation — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For MPI-CDG (Orphanet):

Inheritance: Autosomal recessive
Onset: Infancy, Neonatal

Similar variants

MPI c.145-1G>C Likely pathogenic ★★ same condition
MPI c.16+2T>C Likely pathogenic ★★ same condition
MPI c.488-1G>C Pathogenic/Likely pathogenic ★★ same condition
MPI c.488-2A>G Likely pathogenic ★★ same condition
MPI c.844+1G>A Likely pathogenic ★★ same condition
MPI c.845-2A>G Likely pathogenic ★★ same condition
MPI p.Arg219Gln Pathogenic ★★ ⚠ same condition
MPI p.Arg418His Pathogenic/Likely pathogenic ★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/mpi-p-phe256 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown