Descriptive Epidemiology of Spinal Muscular Atrophy Type I in Estonia

Vaidla, Eve; Talvik, Inga; Kulla, Andres; Kahre, Tiina; Hämarik, Malle; Napa, Aita; Metsvaht, Tuuli; Piirsoo, Andres; Talvik, Tiina

doi:10.1159/000096128

Cited by 12 publications

(5 citation statements)

References 26 publications

(31 reference statements)

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“…The calculations are also based on small patient populations. Nonetheless, the number of patients diagnosed genetically is generally comparable or even higher than reported in previous epidemiological studies [13–17], at least in countries, where genetic testing is readily available.…”

Section: Discussionmentioning

confidence: 50%

A multi-source approach to determine SMA incidence and research ready population

et al. 2017

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In spinal muscular atrophy (SMA), degeneration of motor neurons causes progressive muscular weakness, which is caused by homozygous deletion of the SMN1 gene. Available epidemiological data on SMA are scarce, often outdated, and limited to relatively small regions or populations. Combining data from different sources including genetic laboratories and patient registries may provide better insight of the disease epidemiology. To investigate the incidence of genetically confirmed SMA, and the number of patients who are able and approachable to participate in new clinical trials and observational research, we used both genetic laboratories, the TREAT-NMD Global SMA Patient Registry and the Care and Trial Sites Registry (CTSR). In Europe, 4653 patients were genetically diagnosed by the genetic laboratories in the 5-year period 2011 to 2015, with 992 diagnosed in 2015 alone. The data provide an estimated incidence of SMA in Europe of 1 in 3900–16,000 live births. Patient numbers in the national patient registries and CTSR were considerably lower. By far, most patients registered in the national patient registries and the CTSR live in Europe and are reported to have SMA type II. Considerable differences between countries in patient participation in the registries were observed. Our findings indicate that not all patients with SMA are accessed by specialist healthcare services and these patients may not have access to research opportunities and optimal care.Electronic supplementary materialThe online version of this article (doi:10.1007/s00415-017-8549-1) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 50%

A multi-source approach to determine SMA incidence and research ready population

et al. 2017

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“…In Estonia, the birth prevalence of genetically confirmed SMA has previously been reported in a smaller cohort (15 patients) between the years 1994–2003 as 1:8,655 ( Vaidla et al, 2006 ). The present study shows similar results (1:8,286), which indicates that our diagnostic efficacy has stayed on the same level.…”

Section: Discussionmentioning

confidence: 91%

The Birth Prevalence of Spinal Muscular Atrophy: A Population Specific Approach in Estonia

et al. 2021

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Background: Rare diseases are an important population health issue and many promising therapies have been developed in recent years. In light of novel genetic treatments expected to significantly improve spinal muscular atrophy (SMA) patients’ quality of life and the urgent need for SMA newborn screening (NBS), new epidemiological data were needed to implement SMA NBS in Estonia.Objective: We aimed to describe the birth prevalence of SMA in the years 1996–2020 and to compare the results with previously published data.Methods: We retrospectively analyzed clinical and laboratory data of SMA patients referred to the Department of Clinical Genetics of Tartu University Hospital and its branch in Tallinn.Results: Fifty-seven patients were molecularly diagnosed with SMA. SMA birth prevalence was 1 per 8,286 (95% CI 1 per 6,130–11,494) in Estonia. Patients were classified as SMA type 0 (1.8%), SMA I (43.9%), SMA II (22.8%), SMA III (29.8%), and SMA IV (1.8%). Two patients were compound heterozygotes with an SMN1 deletion in trans with a novel single nucleotide variant NM_000344.3:c.410dup, p.(Asn137Lysfs*11). SMN2 copy number was assessed in 51 patients.Conclusion: In Estonia, the birth prevalence of SMA is similar to the median birth prevalence in Europe. This study gathered valuable information on the current epidemiology of SMA, which can guide the implementation of spinal muscular atrophy to the newborn screening program in Estonia.

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“…Although SMA type I is expected to account for more than half of all new SMA cases [30], the studies that examined a SMA type I only showed a prevalence of 0.04 to 0.28 per 100,000 [24, 25, 31–34], which is much lower than the 1–2 per 100,000 persons noted for all SMA. Due to its severity, patients with SMA type I have a short life expectancy.…”

Section: Prevalence and Incidence Of Smamentioning

confidence: 99%

Prevalence, incidence and carrier frequency of 5q–linked spinal muscular atrophy – a literature review

Verhaart

Robertson

Wilson

et al. 2017

Orphanet J Rare Dis

456

389

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Spinal muscular atrophy linked to chromosome 5q (SMA) is a recessive, progressive, neuromuscular disorder caused by bi-allelic mutations in the SMN1 gene, resulting in motor neuron degeneration and variable presentation in relation to onset and severity. A prevalence of approximately 1–2 per 100,000 persons and incidence around 1 in 10,000 live births have been estimated with SMA type I accounting for around 60% of all cases. Since SMA is a relatively rare condition, studies of its prevalence and incidence are challenging. Most published studies are outdated and therefore rely on clinical rather than genetic diagnosis. Furthermore they are performed in small cohorts in small geographical regions and only study European populations. In addition, the heterogeneity of the condition can lead to delays and difficulties in diagnosing the condition, especially outside of specialist clinics, and contributes to the challenges in understanding the epidemiology of the disease. The frequency of unaffected, heterozygous carriers of the SMN1 mutations appears to be higher among Caucasian and Asian populations compared to the Black (Sub-Saharan African ancestry) population. However, carrier frequencies cannot directly be translated into incidence and prevalence, as very severe (death in utero) and very mild (symptom free in adults) phenotypes carrying bi-allelic SMN1 mutations exist, and their frequency is unknown.More robust epidemiological data on SMA covering larger populations based on accurate genetic diagnosis or newborn screening would be helpful to support planning of clinical studies, provision of care and therapies and evaluation of outcomes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-017-0671-8) contains supplementary material, which is available to authorized users.

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Descriptive Epidemiology of Spinal Muscular Atrophy Type I in Estonia

Cited by 12 publications

References 26 publications

A multi-source approach to determine SMA incidence and research ready population

A multi-source approach to determine SMA incidence and research ready population

The Birth Prevalence of Spinal Muscular Atrophy: A Population Specific Approach in Estonia

Prevalence, incidence and carrier frequency of 5q–linked spinal muscular atrophy – a literature review

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