Sinoatrial Node Dysfunction and Deafness (SANDD): Comprehensive Disease-Characteristics Report

Executive summary and evidence scope

Sinoatrial node dysfunction and deafness (SANDD) is an ultra-rare, autosomal-recessive calcium-channelopathy caused by biallelic loss-of-function variants in CACNA1D, which encodes the pore-forming α1D subunit of the CaV1.3 L-type voltage-gated calcium channel. The defining manifestations are congenital sensorineural deafness and early-onset sinoatrial-node dysfunction, often accompanied by atrioventricular conduction disease. The strongest human evidence remains a small number of consanguineous families; therefore, prevalence, penetrance, long-term survival, quality-of-life, and treatment-response estimates are not available at population level. Open Targets maps only CACNA1D to this disease, supported principally by the original human study, PMID 21131953. (OpenTargets Search: Sinoatrial node dysfunction and deafness-CACNA1D, torrente2020channelopathiesofvoltagegated pages 5-7)

This report distinguishes classic SANDD—biallelic CACNA1D loss of function—from dominant/de novo CACNA1D disorders caused by gain of function or transcript-dependent mixed effects. Those disorders may produce epilepsy, autism, developmental disability, primary aldosteronism, or hyperinsulinism and must not be merged with SANDD. (rinne2022wholeexomesequencing pages 2-4, rinne2022wholeexomesequencing pages 1-2, rinne2022wholeexomesequencing pages 9-11)

The following table provides a knowledge-base-oriented synopsis.

Table: This table condenses the most actionable disease-knowledge elements for Sinoatrial Node Dysfunction and Deafness, including identifiers, gene-mechanism links, phenotypes, models, and explicit evidence gaps. It is designed for direct knowledge-base extraction while separating established human evidence from model-supported inference.

1. Disease information

Definition and identifiers

SANDD is a congenital syndromic disorder linking failure of cardiac pacemaking with deafness. It is classified as a Mendelian channelopathy.

• Preferred name: Sinoatrial node dysfunction and deafness
• Synonyms: SANDD; SANDD syndrome; sinus node dysfunction and deafness; sino-atrial node dysfunction and deafness
• MONDO: MONDO:0013960
• OMIM phenotype: 614896
• Causal gene: CACNA1D, Ensembl ENSG00000157388, encoding calcium voltage-gated channel subunit α1D/CaV1.3 (OpenTargets Search: Sinoatrial node dysfunction and deafness-CACNA1D, torrente2020channelopathiesofvoltagegated pages 5-7)
• MeSH: No disease-specific MeSH descriptor was identified; broader descriptors include Sick Sinus Syndrome, Bradycardia, and Hearing Loss, Sensorineural.
• ICD-10/ICD-11: No SANDD-specific code was identified. Component manifestations would ordinarily be coded separately—for example, sick sinus syndrome/conduction disease and congenital sensorineural hearing loss.
• Orphanet: No confidently verified disease-specific Orphanet identifier was recovered in the searched evidence; it should not be inferred from OMIM or MONDO.

Data provenance

The evidence is aggregated disease-level information derived from published pedigrees, functional expression studies, and animal models, not an EHR-scale patient dataset. Seven consanguineous Pakistani families have been described in the literature synthesis, but detailed denominators and standardized phenotype frequencies are unavailable. (torrente2020channelopathiesofvoltagegated pages 5-7)

2. Etiology, risk, and protective factors

Causal factor

The primary cause is germline biallelic CACNA1D loss of function. The best-characterized recurrent lesion is a three-base-pair insertion in alternatively spliced exon 8B, variously reported as p.Gly403dup, p.403_404insGly, or p.403-404InsGly. The mutant protein reaches the plasma membrane but generates no functional Ca²⁺ current, indicating a channel-conduction/gating defect rather than simple trafficking failure. A second reported SANDD-associated missense variant is p.Ala376Val. (rinne2022wholeexomesequencing pages 9-11, torrente2020channelopathiesofvoltagegated pages 7-9, torrente2020channelopathiesofvoltagegated pages 5-7)

Risk factors

• Genetic: Homozygosity or compound biallelic pathogenic CACNA1D loss-of-function variants is the principal risk. Heterozygous relatives in the classic pedigrees were clinically unaffected, supporting recessive inheritance. (torrente2020channelopathiesofvoltagegated pages 7-9)
• Family structure: Consanguinity and ancestry from a founder population are important ascertainment/risk factors in the known families. The recurrent insertion has been reported across seven consanguineous families from Khyber Pakhtunkhwa, Pakistan. (torrente2020channelopathiesofvoltagegated pages 5-7)
• Environmental, infectious, occupational, lifestyle, age, or sex risks: None are established for occurrence of this congenital Mendelian disorder.
• Modifiers: No validated modifier genes are known. Variable cardiac severity could plausibly reflect other pacemaker-current genes, autonomic tone, medications, or epigenetic background, but this remains unproven for SANDD.

Protective factors and gene–environment interactions

No protective allele, diet, exposure, medication, or lifestyle intervention has been shown to prevent SANDD. Avoidance of drugs that further depress sinoatrial or atrioventricular conduction is clinically prudent but is tertiary risk management, not primary prevention. No SANDD-specific gene–environment interaction has been demonstrated.

3. Phenotypes

Core phenotype profile

1. Congenital sensorineural hearing impairment/deafness—a defining, generally severe-to-profound phenotype. Suggested terms: HP:0000407 Sensorineural hearing impairment, HP:0008619 Congenital hearing impairment. Mouse and human evidence localizes the defect to CaV1.3-dependent cochlear inner-hair-cell physiology. (rinne2022wholeexomesequencing pages 2-4, rinne2022wholeexomesequencing pages 1-2)
2. Sinus bradycardia/sinoatrial-node dysfunction—reported daytime rates were approximately 38–52 beats/min, falling below 35 beats/min at night in affected homozygotes. Suggested terms: HP:0001649 Bradycardia and a suitable HPO term for sick sinus syndrome/sinus-node dysfunction. (torrente2020channelopathiesofvoltagegated pages 7-9)
3. Sinus pauses and sinoatrial exit block—episodic manifestations superimposed on chronic bradycardia. (torrente2020channelopathiesofvoltagegated pages 7-9)
4. Atrioventricular conduction disease—severity ranges from second-degree AV block to complete heart block. Suggested terms: HP:0011706 Second-degree atrioventricular block and HP:0004762 Complete atrioventricular block. (torrente2020channelopathiesofvoltagegated pages 7-9)
5. Exercise intolerance, dizziness, fatigue, and syncope—downstream symptoms of bradycardia and chronotropic incompetence; exercise-associated syncope was reported. Suggested terms include HP:0001279 Syncope, fatigue, dizziness, and exercise intolerance. (torrente2020channelopathiesofvoltagegated pages 7-9)

Precise percentages cannot be responsibly assigned because published evidence lacks a complete standardized denominator. Congenital deafness and sinus-node disease define classic SANDD, whereas AV block and symptomatic syncope vary in severity.

Onset, severity, progression, and quality of life

Deafness is congenital. Cardiac disease is congenital or recognized in childhood and appears chronic, with variable severity and episodic pauses/syncope. There is no evidence for spontaneous remission. Deafness affects communication and education, while bradycardia, syncope, and exercise intolerance restrict physical activity and create injury risk. No SANDD-specific EQ-5D, SF-36, PROMIS, or hearing-related quality-of-life study was identified.

4. Genetic and molecular information

Gene and protein

CACNA1D encodes CaV1.3, an L-type voltage-gated calcium-channel α1 subunit. CaV1.3 is particularly important in adult atrial, sinoatrial, and atrioventricular nodal tissue and in cochlear inner hair cells. (mesirca2016rescuingcardiacautomaticity pages 3-5, rinne2022wholeexomesequencing pages 1-2)

Variant interpretation

• p.Gly403dup/p.403_404insGly: homozygous germline in affected families; three-base-pair in-frame insertion; functionally electrically silent despite membrane localization. This constitutes strong pathogenic evidence from segregation, phenotype specificity, and functional assay. (torrente2020channelopathiesofvoltagegated pages 7-9, torrente2020channelopathiesofvoltagegated pages 5-7)
• p.Ala376Val: reported in another family with the same SANDD phenotype, but the retrieved evidence provides less detailed segregation and functional information than for p.Gly403dup. (rinne2022wholeexomesequencing pages 9-11, torrente2020channelopathiesofvoltagegated pages 7-9)

Current ClinVar classifications and exact gnomAD allele counts were not recovered and should be checked against the current transcript and genome build before database ingestion. The recurrent variant’s multiple protein descriptions also require HGVS normalization against the selected CACNA1D transcript. The disease alleles are germline, not somatic.

No established chromosomal rearrangement, copy-number syndrome, repeat expansion, mitochondrial variant, modifier gene, or disease-specific epigenetic signature is known. No anticipation or germline mosaicism has been reported. Carrier frequency cannot be calculated from the family reports.

Important allelic distinction

A heterozygous p.Arg930His CACNA1D variant was reported in an autosomal-dominant family with sinus-node dysfunction, epilepsy, learning problems, and ADHD but not classic congenital deafness. It produced gain of function in the short, brain-enriched isoform and loss of function in the long isoform. This is mechanistically and clinically distinct from recessive SANDD. (rinne2022wholeexomesequencing pages 2-4, rinne2022wholeexomesequencing pages 1-2, rinne2022wholeexomesequencing pages 11-12)

5. Environmental information

No toxin, radiation exposure, pollutant, occupation, diet, smoking pattern, alcohol use, or infectious agent is known to cause classic SANDD. Such factors can independently worsen acquired bradyarrhythmia or hearing loss, but there is no evidence that they initiate the CACNA1D syndrome. Consequently, environmental and infectious-agent fields should be populated as not established/not applicable, rather than as negative causal claims.

6. Mechanism and pathophysiology

Cardiac causal chain

Upstream: biallelic CACNA1D loss of function → absent or markedly reduced CaV1.3-mediated L-type Ca²⁺ current.

Cellular: CaV1.3 normally activates at more negative voltages than CaV1.2—approximately −45 mV versus −25 mV—allowing it to contribute during diastolic depolarization of sinoatrial pacemaker cells. Under β-adrenergic activation, relevant CaV1.3 activity can extend to approximately −55 to −60 mV. CaV1.3 also supports RyR2-dependent local Ca²⁺ release and NCX-mediated inward current and contributes to sustained inward current. (torrente2020channelopathiesofvoltagegated pages 5-7, torrente2020channelopathiesofvoltagegated pages 9-11)

Downstream: reduced diastolic inward current and impaired Ca²⁺-clock/membrane-clock coupling → slowed spontaneous pacemaker depolarization → sinus bradycardia, pauses, exit block, and chronotropic incompetence. Loss of CaV1.3 in atrioventricular nodal cells similarly slows or blocks conduction. In global knockout mice, SAN L-type current density is reduced by approximately 60–70%. (mesirca2016rescuingcardiacautomaticity pages 3-5, torrente2020channelopathiesofvoltagegated pages 22-24)

Suggested GO annotations include GO:0005245 voltage-gated calcium-channel activity, GO:0006816 calcium-ion transport, cardiac action-potential regulation, membrane depolarization, regulation of heart rate, and calcium-dependent exocytosis.

Auditory causal chain

CACNA1D loss → failure of CaV1.3-mediated Ca²⁺ entry in cochlear inner hair cells → impaired presynaptic ribbon-synapse transmitter release and abnormal pre-hearing Ca²⁺ action potentials/gene-expression programs → arrested inner-hair-cell maturation, altered BK/SK2 channel expression, and eventual hair-cell degeneration → congenital severe-to-profound sensorineural deafness. (rinne2022wholeexomesequencing pages 1-2)

Suggested cells and processes are CL:0000586 hearing receptor cell, cochlear inner hair cell, sensory perception of sound, inner-ear receptor-cell differentiation, calcium-dependent exocytosis, and ribbon-synapse transmission.

Other mechanistic domains

No SANDD-specific immune, inflammatory, fibrotic, metabolic, lipidomic, metabolomic, proteomic, single-cell, spatial-transcriptomic, or epigenomic signature has been established. The primary abnormality is an ion-channel conduction defect, not inflammation or energy-metabolism failure.

7. Anatomical structures affected

• Heart/conduction system: heart (UBERON:0000948), sinoatrial node, atrioventricular node, atrial conduction tissue; principal cells are specialized nodal pacemaker/conduction cardiomyocytes. (mesirca2016rescuingcardiacautomaticity pages 3-5, rinne2022wholeexomesequencing pages 1-2)
• Inner ear: inner ear (UBERON:0001844), cochlea (UBERON:0001690), organ of Corti, and especially bilateral cochlear inner hair cells and their ribbon synapses. (rinne2022wholeexomesequencing pages 1-2)
• Subcellular localization: CaV1.3 resides in the plasma membrane; disease-relevant signaling also involves presynaptic active zones/ribbon synapses, sarcolemmal ion-channel complexes, sarcoplasmic-reticulum RyR2 release sites, and NCX-containing membrane microdomains.
• Lateralization: Hearing loss is expected to be bilateral; no consistent cardiac anatomical lateralization applies.

8. Temporal development

The auditory phenotype begins prenatally or at birth, reflecting developmental failure of inner-hair-cell function and maturation. Cardiac bradyarrhythmia is congenital/childhood-onset and chronic. Severity can fluctuate with sleep, exercise, autonomic state, and intermittent conduction block; the documented lower nocturnal heart rates illustrate physiologic modulation of an underlying fixed channel defect. (torrente2020channelopathiesofvoltagegated pages 7-9)

No validated staging system exists. A practical clinical sequence is: congenital deafness and baseline bradycardia → recognition of pauses/chronotropic incompetence or AV block → symptomatic dizziness, exercise intolerance, or syncope → pacemaker consideration. Disease duration is lifelong, and no spontaneous remission window is documented.

9. Inheritance and population

Inheritance is autosomal recessive. Heterozygous relatives in classic families were reported as phenotypically normal, suggesting that one functional allele is usually sufficient, although formal lifelong penetrance studies are unavailable. (torrente2020channelopathiesofvoltagegated pages 7-9)

The recurrent variant was found in seven consanguineous families from Khyber Pakhtunkhwa, Pakistan, consistent with a founder effect or geographically concentrated allele. No unbiased prevalence, incidence, carrier-frequency, sex-ratio, or age-distribution estimate exists. There is no evidence of sex-limited expression, anticipation, or a broad endemic distribution. (torrente2020channelopathiesofvoltagegated pages 5-7)

For counseling, when both parents are confirmed heterozygous carriers, each pregnancy has the standard autosomal-recessive probabilities: 25% affected, 50% carrier, and 25% unaffected/non-carrier.

10. Diagnostics

Clinical evaluation

1. Cardiac: resting 12-lead ECG; prolonged Holter/event monitoring to quantify minimum and mean heart rates, sinus pauses, exit block, and AV block; exercise testing for chronotropic incompetence; echocardiography to evaluate structural heart disease and alternative causes. Electrophysiology study may be considered when noninvasive findings are inconclusive.
2. Audiology: newborn or diagnostic auditory brainstem response, otoacoustic emissions, pure-tone audiometry when developmentally appropriate, tympanometry, speech testing, and assessment for cochlear implantation.
3. Laboratory exclusion: electrolytes, thyroid function, medication review, and other tests directed at acquired bradycardia; these do not diagnose SANDD.

Genetic testing strategy

• When congenital bilateral sensorineural deafness co-occurs with marked sinus bradycardia or AV block, perform CACNA1D sequencing with deletion/duplication analysis or a combined hearing-loss/arrhythmia panel.
• WES or WGS is appropriate when the phenotype is atypical, panel testing is negative, or a second diagnosis is possible. WES identified a distinct dominant CACNA1D syndrome in a sinus-node-dysfunction cohort, illustrating the value of broad testing but also the need for mechanism-specific interpretation. (rinne2022wholeexomesequencing pages 2-4, rinne2022wholeexomesequencing pages 1-2)
• Confirm phase and segregation by parental testing. A molecular diagnosis of recessive SANDD requires two pathogenic/likely pathogenic loss-of-function alleles in trans plus compatible phenotype.
• CMA, karyotype, FISH, mitochondrial testing, repeat-expansion testing, RNA sequencing, proteomics, metabolomics, and liquid biopsy are not first-line unless another diagnosis is suspected.

Differential diagnosis

Important alternatives include isolated congenital deafness plus unrelated bradycardia; Jervell and Lange-Nielsen syndrome (biallelic KCNQ1/KCNE1, deafness with prolonged QT); HCN4-related sinus-node disease; SCN5A-related conduction disease; LMNA-related conduction/cardiomyopathy; mitochondrial deafness syndromes; and dominant CACNA1D neurodevelopmental/endocrine channelopathy. The ECG QT interval, neurologic/endocrine phenotype, inheritance, and molecular findings distinguish these conditions. CACNA1D’s recessive-versus-dominant allelic spectrum is analogous to other channel genes in which dosage and functional direction determine phenotype. (rinne2022wholeexomesequencing pages 9-11)

Cascade testing of relatives is appropriate; universal population or newborn genomic screening for SANDD is not established.

11. Outcome and prognosis

No disease-specific 5- or 10-year survival, mortality, life-expectancy, hospitalization, or quality-of-life estimates exist. Likely major morbidities are recurrent syncope/injury, exercise limitation, progression of conduction disease, pacemaker dependence, and lifelong communication disability. Atrial fibrillation was inducible in Cacna1d-null mice but was not reported in the summarized human SANDD cases, so it should not be coded as an established human feature. (torrente2020channelopathiesofvoltagegated pages 7-9)

Prognosis is expected to improve substantially with recognition and treatment of clinically important bradyarrhythmia and with early hearing rehabilitation, but syndrome-specific response rates are unavailable. Severity of bradycardia, pause duration, high-grade AV block, syncope, and failure of heart rate to rise with exercise are clinically relevant risk indicators; no molecular prognostic biomarker beyond causal genotype has been validated.

12. Treatment

Current real-world management

• Permanent cardiac pacemaker: standard definitive therapy for symptomatic sinus-node dysfunction, clinically consequential pauses, chronotropic incompetence, or advanced AV block. This treats the electrical consequence but does not restore CACNA1D function or hearing. Suggested NCIT concept: cardiac pacemaker implantation. Reviews emphasize that current SND management is primarily symptomatic and that electronic pacing remains the established intervention. (mesirca2016rescuingcardiacautomaticity pages 1-2)
• Acute symptomatic bradycardia: managed under standard resuscitation/cardiology protocols; atropine or temporary pacing may be used according to clinical context, but no SANDD-specific evidence exists.
• Hearing care: early audiology, hearing devices when residual function permits, cochlear-implant evaluation for severe/profound loss, speech-language therapy, educational accommodations, and communication support. Syndrome-specific cochlear-implant outcomes have not been published in the recovered literature.
• Medication review: avoid or carefully supervise drugs that further slow sinus or AV nodal function.

Experimental and precision approaches

In Cacna1d-null mice, inhibition of the acetylcholine-activated potassium current IKACh—including experimental inhibitors such as tertiapin-Q—restored a more favorable inward/outward current balance and rescued bradycardia. This is preclinical proof of concept, not approved SANDD treatment. (mesirca2016rescuingcardiacautomaticity pages 1-2, torrente2020channelopathiesofvoltagegated pages 9-11)

No SANDD-specific gene therapy, RNA therapy, CRISPR trial, cell therapy, or registered interventional clinical trial was identified. CaV1.3 blockers such as isradipine are being explored for gain-of-function CACNA1D neurodevelopmental/endocrine disease; blocking an already loss-of-function channel is not a rational SANDD treatment. In 2024 expert analysis, isradipine benefit was discussed in a gain-of-function mouse model, whereas human CaV1.3 loss of function remained a distinct bradycardia-deafness syndrome. (ortner2024iscav1.3a pages 6-6)

13. Prevention

Primary prevention by lifestyle modification, vaccination, or prophylactic medication is not possible for a germline recessive channelopathy. Relevant measures are:

• Genetic counseling and carrier testing in affected families.
• Reproductive options: prenatal diagnosis or preimplantation genetic testing when familial variants are known.
• Secondary prevention: newborn hearing screening, early ECG/Holter evaluation in at-risk children, and cascade genetic testing.
• Tertiary prevention: timely pacing to prevent bradycardic syncope and high-grade block; early hearing intervention to reduce language and educational consequences; avoidance of conduction-slowing drugs when possible.

There is no applicable vaccine, infectious prophylaxis, or population-wide public-health screening program specific to SANDD.

14. Other species and natural disease

No naturally occurring veterinary SANDD syndrome or breed-associated CACNA1D disorder was identified. The principal comparative species is the laboratory mouse, Mus musculus (NCBI Taxonomy 10090), with ortholog Cacna1d. The cardiac and cochlear functions of CaV1.3 are evolutionarily conserved, but existing mouse disease is experimentally engineered rather than naturally occurring. There is no infectious transmission or zoonotic potential.

15. Model organisms and experimental systems

Mouse models

Global Cacna1d/CaV1.3 knockout mice reproduce major human features: bradycardia, sinoatrial dysfunction, AV block, and deafness. SAN L-type Ca²⁺ current is reduced by approximately 60–70%, making this a strong mechanistic model for membrane-clock/Ca²⁺-clock coupling and for preclinical pacemaker-current interventions. (mesirca2016rescuingcardiacautomaticity pages 3-5, torrente2020channelopathiesofvoltagegated pages 7-9, torrente2020channelopathiesofvoltagegated pages 22-24)

Cochlea-specific Cacna1d deletion produces profound hearing loss, absent normal BK-channel upregulation, persistence of immature SK2 expression, and arrested inner-hair-cell differentiation. This demonstrates a cochlea-autonomous requirement for CaV1.3, although complex Cre/reporter constructs can themselves alter expression or cause GFP toxicity and therefore require careful controls. (rinne2022wholeexomesequencing pages 1-2)

In-vitro systems

Heterologous channel-expression and patch-clamp studies show that the recurrent p.Gly403dup protein reaches the cell surface but produces no measurable Ca²⁺ current. These assays provide direct evidence of loss of channel conductance but do not reproduce the multicellular architecture or autonomic regulation of the SAN and cochlea. (torrente2020channelopathiesofvoltagegated pages 7-9, torrente2020channelopathiesofvoltagegated pages 5-7)

No validated SANDD patient-derived iPSC pacemaker-cell model, cochlear organoid, large-animal model, CRISPR screen, or disease-specific multi-omics model was identified in the retrieved evidence.

Recent developments and expert assessment, 2023–2024

Recent cardiac reviews continue to identify CaV1.3 as unusually attractive for nodal-selective mechanistic study because adult cardiac expression is concentrated in atrial and nodal tissue rather than being ubiquitous across ventricular myocardium. Nonetheless, therapeutic work in 2023–2024 has focused more heavily on CACNA1D gain-of-function neurodevelopmental disease than on SANDD. The emerging expert consensus is therefore that molecular direction matters: CaV1.3 inhibition may be relevant to gain-of-function disease, whereas SANDD requires restoration or compensation of deficient pacemaker and cochlear signaling. (ortner2024iscav1.3a pages 6-6)

The most mature SANDD-relevant translational idea remains compensatory ion-channel targeting, exemplified by IKACh inhibition in knockout mice. Gene replacement or editing is conceptually attractive but faces the challenge of delivering therapy to two specialized targets—cardiac nodal cells and cochlear inner hair cells—potentially during different developmental windows. (mesirca2016rescuingcardiacautomaticity pages 1-2, torrente2020channelopathiesofvoltagegated pages 9-11)

Key sources, dates, and URLs

1. Baig et al. “Loss of CaV1.3 (CACNA1D) function in a human channelopathy with bradycardia and congenital deafness.” Nature Neuroscience. Published December 2010/January 2011 issue. PMID 21131953. DOI: https://doi.org/10.1038/nn.2694. This is the landmark primary human report underlying the disease association. (OpenTargets Search: Sinoatrial node dysfunction and deafness-CACNA1D)
2. Torrente et al. “Channelopathies of voltage-gated L-type CaV1.3/α1D and T-type CaV3.1/α1G Ca²⁺ channels in dysfunction of heart automaticity.” Pflügers Archiv. Published June 2020. DOI: https://doi.org/10.1007/s00424-020-02421-1. (torrente2020channelopathiesofvoltagegated pages 5-7, torrente2020channelopathiesofvoltagegated pages 7-9)
3. Mesirca et al. “Rescuing cardiac automaticity in L-type CaV1.3 channelopathies and beyond.” Journal of Physiology. Published October 2016. DOI: https://doi.org/10.1113/JP270678. (mesirca2016rescuingcardiacautomaticity pages 3-5, mesirca2016rescuingcardiacautomaticity pages 1-2)
4. Rinné et al. “Whole Exome Sequencing Identifies a Heterozygous Variant in the CaV1.3 Gene CACNA1D Associated with Familial Sinus Node Dysfunction and Focal Idiopathic Epilepsy.” International Journal of Molecular Sciences. Published November 2022. DOI: https://doi.org/10.3390/ijms232214215. Its abstract states: “So far, homozygous loss of function mutations in CACNA1D encoding the CaV1.3 α1-subunit are described in congenital sinus node dysfunction and deafness.” This source is especially useful for separating classic SANDD from dominant mixed-effect disease. (rinne2022wholeexomesequencing pages 2-4, rinne2022wholeexomesequencing pages 1-2)
5. Ortner. “Is CaV1.3 a feasible therapeutic target for a rare neurodevelopmental disorder?” Expert Opinion on Therapeutic Targets. Published December 2024. DOI: https://doi.org/10.1080/14728222.2024.2442428. This is authoritative recent analysis but pertains primarily to CACNA1D gain-of-function disease, not SANDD therapy. (ortner2024iscav1.3a pages 6-6)

Evidence limitations

SANDD has not been characterized through registries, prospective natural-history cohorts, randomized trials, or population screening. Consequently, disease prevalence, incidence, exact phenotype frequencies, penetrance by age, carrier frequency, sex ratio, survival, mortality, quality-of-life scores, cochlear-implant outcomes, and genotype-specific prognosis remain unknown. Database fields for those domains should be marked “not available—ultra-rare family-level evidence”, not zero. The most secure knowledge-base assertions are the MONDO/OMIM mapping, recessive CACNA1D loss-of-function mechanism, congenital deafness, severe sinus bradycardia with possible AV block, and recapitulation in Cacna1d-null mice. (OpenTargets Search: Sinoatrial node dysfunction and deafness-CACNA1D, torrente2020channelopathiesofvoltagegated pages 5-7, torrente2020channelopathiesofvoltagegated pages 7-9)

References

1. (OpenTargets Search: Sinoatrial node dysfunction and deafness-CACNA1D): Open Targets Query (Sinoatrial node dysfunction and deafness-CACNA1D, 1 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.

2. (torrente2020channelopathiesofvoltagegated pages 5-7): Angelo G. Torrente, Pietro Mesirca, Isabelle Bidaud, and Matteo E. Mangoni. Channelopathies of voltage-gated l-type cav1.3/α1d and t-type cav3.1/α1g ca2+ channels in dysfunction of heart automaticity. Pflügers Archiv - European Journal of Physiology, 472:817-830, Jun 2020. URL: https://doi.org/10.1007/s00424-020-02421-1, doi:10.1007/s00424-020-02421-1. This article has 32 citations.

3. (rinne2022wholeexomesequencing pages 2-4): Susanne Rinné, Birgit Stallmeyer, Alexandra Pinggera, Michael F. Netter, Lina A. Matschke, Sven Dittmann, Uwe Kirchhefer, Ulrich Neudorf, Joachim Opp, Jörg Striessnig, Niels Decher, and Eric Schulze-Bahr. Whole exome sequencing identifies a heterozygous variant in the cav1.3 gene cacna1d associated with familial sinus node dysfunction and focal idiopathic epilepsy. International Journal of Molecular Sciences, 23:14215, Nov 2022. URL: https://doi.org/10.3390/ijms232214215, doi:10.3390/ijms232214215. This article has 22 citations.

4. (rinne2022wholeexomesequencing pages 1-2): Susanne Rinné, Birgit Stallmeyer, Alexandra Pinggera, Michael F. Netter, Lina A. Matschke, Sven Dittmann, Uwe Kirchhefer, Ulrich Neudorf, Joachim Opp, Jörg Striessnig, Niels Decher, and Eric Schulze-Bahr. Whole exome sequencing identifies a heterozygous variant in the cav1.3 gene cacna1d associated with familial sinus node dysfunction and focal idiopathic epilepsy. International Journal of Molecular Sciences, 23:14215, Nov 2022. URL: https://doi.org/10.3390/ijms232214215, doi:10.3390/ijms232214215. This article has 22 citations.

5. (rinne2022wholeexomesequencing pages 9-11): Susanne Rinné, Birgit Stallmeyer, Alexandra Pinggera, Michael F. Netter, Lina A. Matschke, Sven Dittmann, Uwe Kirchhefer, Ulrich Neudorf, Joachim Opp, Jörg Striessnig, Niels Decher, and Eric Schulze-Bahr. Whole exome sequencing identifies a heterozygous variant in the cav1.3 gene cacna1d associated with familial sinus node dysfunction and focal idiopathic epilepsy. International Journal of Molecular Sciences, 23:14215, Nov 2022. URL: https://doi.org/10.3390/ijms232214215, doi:10.3390/ijms232214215. This article has 22 citations.

6. (mesirca2016rescuingcardiacautomaticity pages 1-2): Pietro Mesirca, Isabelle Bidaud, and Matteo E. Mangoni. Rescuing cardiac automaticity in l‐type cav1.3 channelopathies and beyond. The Journal of Physiology, 594:5869-5879, Oct 2016. URL: https://doi.org/10.1113/jp270678, doi:10.1113/jp270678. This article has 31 citations.

7. (torrente2020channelopathiesofvoltagegated pages 7-9): Angelo G. Torrente, Pietro Mesirca, Isabelle Bidaud, and Matteo E. Mangoni. Channelopathies of voltage-gated l-type cav1.3/α1d and t-type cav3.1/α1g ca2+ channels in dysfunction of heart automaticity. Pflügers Archiv - European Journal of Physiology, 472:817-830, Jun 2020. URL: https://doi.org/10.1007/s00424-020-02421-1, doi:10.1007/s00424-020-02421-1. This article has 32 citations.

8. (torrente2020channelopathiesofvoltagegated pages 22-24): Angelo G. Torrente, Pietro Mesirca, Isabelle Bidaud, and Matteo E. Mangoni. Channelopathies of voltage-gated l-type cav1.3/α1d and t-type cav3.1/α1g ca2+ channels in dysfunction of heart automaticity. Pflügers Archiv - European Journal of Physiology, 472:817-830, Jun 2020. URL: https://doi.org/10.1007/s00424-020-02421-1, doi:10.1007/s00424-020-02421-1. This article has 32 citations.

9. (mesirca2016rescuingcardiacautomaticity pages 3-5): Pietro Mesirca, Isabelle Bidaud, and Matteo E. Mangoni. Rescuing cardiac automaticity in l‐type cav1.3 channelopathies and beyond. The Journal of Physiology, 594:5869-5879, Oct 2016. URL: https://doi.org/10.1113/jp270678, doi:10.1113/jp270678. This article has 31 citations.

10. (torrente2020channelopathiesofvoltagegated pages 9-11): Angelo G. Torrente, Pietro Mesirca, Isabelle Bidaud, and Matteo E. Mangoni. Channelopathies of voltage-gated l-type cav1.3/α1d and t-type cav3.1/α1g ca2+ channels in dysfunction of heart automaticity. Pflügers Archiv - European Journal of Physiology, 472:817-830, Jun 2020. URL: https://doi.org/10.1007/s00424-020-02421-1, doi:10.1007/s00424-020-02421-1. This article has 32 citations.

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