SLC6A2

Chr 16AD

solute carrier family 6 member 2

Also known as: NAT1, NET, NET1, SLC6A5

NCBI Gene: 6530 ENSG00000103546 UniProt: P23975

This gene encodes a member of the sodium:neurotransmitter symporter family. This member is a multi-pass membrane protein, which is responsible for reuptake of norepinephrine into presynaptic nerve terminals and is a regulator of norepinephrine homeostasis. Mutations in this gene cause orthostatic intolerance, a syndrome characterized by lightheadedness, fatigue, altered mentation and syncope. Alternatively spliced transcript variants encoding different isoforms have been identified in this gene.[provided by RefSeq, Feb 2010]

Primary Disease Associations & Inheritance

?Orthostatic intoleranceMIM #604715

Active trials

Pathogenic / LP

124

ClinVar variants

Pubs (1 yr)

2.0

Missense Z

0.48

LOEUF

Clinical Summary— SLC6A2

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Population Constraint (gnomAD)

Constrained for loss-of-function variants (OE-LoF 0.26) despite low pLI — interpret in context.

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ClinVar Variants

18 Pathogenic / Likely Pathogenic· 72 VUS of 124 total submissions

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Clinical Trials

1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Moderate LoF intolerance

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.

0.48LOEUF

pLI 0.082

Z-score 3.76

OE 0.26 (0.15–0.48)

Moderately constrained

More LoF-intolerant than ~75% of genes

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.

2.02Z-score

OE missense 0.70 (0.63–0.78)

254 obs / 362.1 exp

Mild constraint

Moderately missense-constrained (top ~2.5%)

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.0.26 (0.15–0.48)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.70 (0.63–0.78)

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.1.16

0≤1.21.6

LoF obs/exp: 8 / 30.4Missense obs/exp: 254 / 362.1Syn Z: -1.56

0.78top 25%

GOF

0.84top 5%

LOF

0.2092th %ile

This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

GOFprediction above median

DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.