Incidence of spinal muscular atrophy in Poland--more frequent than predicted?
BACKGROUND
The application of molecular methods has enhanced and enlarged the diagnostics of spinal muscular atrophy (SMA) and its carriership. It allows for reliable epidemiological studies which are of importance to demography and genetic counseling.


METHODS
This study sought to evaluate the incidence of SMA in Poland, on the basis of the prevalence of the SMN1 gene deletion carrier state in the general population, as well as an analysis of all cases of SMA diagnosed in the years 1998-2005.


RESULTS
The prevalence of the SMN1 gene deletion carrier state was estimated at 1 per 35 persons (17/600), yielding an incidence of SMA equal to 1 per 4,900. By contrast, the incidence of SMA based on the results of the meta-analysis was an estimated 1 per 7,127 in Warsaw and 1 per 9,320 persons across Poland, suggesting that some cases of SMA remain undiagnosed. SMA1 predominated among the diagnoses, accounting for 69% of all cases.


CONCLUSIONS
A high prevalence of the SMN1 deletion carrier state in the general population indicates that SMA could be a more frequent disease than is predicted by the epidemiological data regarding diagnosed cases.
Jedrzejowska
Maria
M
Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland. mariaj@cmdik.pan.pl
Milewski
Michal
M
Zimowski
Janusz
J
Zagozdzon
Pawel
P
Kostera-Pruszczyk
Anna
A
Borkowska
Janina
J
Sielska
Danuta
D
Jurek
Marta
M
Hausmanowa-Petrusewicz
Irena
I
D000208:Acute Disease; D002908:Chronic Disease; D030541:Databases, Genetic / Q000706:statistics & numerical data; D017353:Gene Deletion; D006580:Genetic Carrier Screening / Q000379:methods; D006801:Humans; D015994:Incidence; D009134:Muscular Atrophy, Spinal / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*; D011044:Poland / Q000453:epidemiology; D011237:Predictive Value of Tests; D055533:Survival of Motor Neuron 1 Protein / Q000235:genetics*
C526471:SMN1 protein, human; D055533:Survival of Motor Neuron 1 Protein