SPAG8

Chr 9

sperm associated antigen 8

Also known as: BS-84, CILD28, CT142, HSD-1, SMP1, SPAG3, hSMP-1

NCBI Gene: 26206 ENSG00000137098 UniProt: Q99932

The correlation of anti-sperm antibodies with cases of unexplained infertility implicates a role for these antibodies in blocking fertilization. Improved diagnosis and treatment of immunologic infertility, as well as identification of proteins for targeted contraception, are dependent on the identification and characterization of relevant sperm antigens. The protein encoded by this gene is recognized by sperm agglutinating antibodies from an infertile woman. This protein is localized in germ cells of the testis at all stages of spermatogenesis and is localized to the acrosomal region of mature spermatozoa. This protein interacts with ACT (activator of CREM in testis) and may play a role in CREM (cAMP response element modulator)-ACT-mediated gene transcription during spermatogenesis. This protein may also play a role in spermatogenesis by regulating microtubule formation and cell division. Alternatively spliced variants that encode different protein isoforms have been described but the full-length sequences of only two have been determined. [provided by RefSeq, Jul 2012]

296

ClinVar variants

Pathogenic / LP

0.00

pLI score

Active trials

Clinical Summary— SPAG8

⚡

Population Constraint (gnomAD)

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

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ClinVar Variants

90 Pathogenic / Likely Pathogenic· 158 VUS of 296 total submissions

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.

1.25LOEUF

pLI 0.000

Z-score 0.62

OE 0.86 (0.60–1.25)

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.

0.57Z-score

OE missense 0.90 (0.81–1.00)

253 obs / 279.7 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.0.86 (0.60–1.25)

0≤0.351.4

Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.90 (0.81–1.00)

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.0.98

0≤1.21.6

LoF obs/exp: 20 / 23.2Missense obs/exp: 253 / 279.7Syn Z: 0.13