RFT1

Chr 3AR

RFT1 glycolipid translocator homolog

Intramembrane glycolipid transporter that operates in the biosynthetic pathway of dolichol-linked oligosaccharides, the glycan precursors employed in protein asparagine (N)-glycosylation. The sequential addition of sugars to dolichol pyrophosphate produces dolichol-linked oligosaccharides containing fourteen sugars, including two GlcNAcs, nine mannoses and three glucoses. Once assembled, the oligosaccharide is transferred from the lipid to nascent proteins by oligosaccharyltransferases. The assembly of dolichol-linked oligosaccharides begins on the cytosolic side of the endoplasmic reticulum membrane and finishes in its lumen. RFT1 could mediate the translocation of the cytosolically oriented intermediate DolPP-GlcNAc2Man5, produced by ALG11, into the ER lumen where dolichol-linked oligosaccharides assembly continues (PubMed:18313027, PubMed:19701946). However, the intramembrane lipid transporter activity could not be confirmed in vitro (By similarity)

Primary Disease Associations & Inheritance

Congenital disorder of glycosylation, type InMIM #612015

276

ClinVar variants

Pathogenic / LP

0.00

pLI score

Active trials

Clinical Summary— RFT1

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Gene-Disease Validity (ClinGen)

RFT1-congenital disorder of glycosylation · ARModerate

Moderate evidence — consider for supplementary testing

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

7 Pathogenic / Likely Pathogenic· 110 VUS of 276 total submissions

Some data sources returned errors (1)

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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.

1.09LOEUF

pLI 0.000

Z-score 1.15

OE 0.77 (0.56–1.09)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.

0.97Z-score

OE missense 0.84 (0.76–0.94)

248 obs / 294.7 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.

LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.77 (0.56–1.09)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.84 (0.76–0.94)

0≤0.61.4

Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.96

0≤1.21.6

LoF obs/exp: 23 / 29.8Missense obs/exp: 248 / 294.7Syn Z: 0.33