Which childhood and familial diseases cause sinus node dysfunction (SND)?

Updated: Nov 30, 2018
  • Author: Bharat K Kantharia, MD, FRCP, FAHA, FACC, FESC, FHRS; Chief Editor: Mikhael F El-Chami, MD  more...
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Although rare in children, when SND presents in this population, it is most often seen in those with congenital and acquired heart disease, particularly after corrective cardiac surgery. Familial SSS is rare, with mutations in the cardiac sodium channel gene SCN5A [11, 12]  and the HCN4 gene [13]  (thought to contribute to the SN pacemaker current) responsible for some familial cases.

In a series of 30 children and young adults (age range: 3 days to 25 years) with SND, 22 had significant cardiac disease, and 13 developed SND after cardiac surgery. [14]  The causes of SND were inappropriate sinus bradycardia, sinus arrest, and SA exit block. [14]

In a study of 10 children from 7 families with familial SSS, in which genomic DNA encoding the alpha subunit of the cardiac sodium channel was screened for mutations, compound heterozygous nucleotide changes were identified in 5 children from 3 families, but not in any of over 75 control subjects. [11]

In a series of 38 patients with clinical evidence of Brugada syndrome, 4 had SCN5A mutations. Of these 4 patients, 3 had SND with multiple affected family members. However, mutations in SCN5A are not pathognomonic for SND, as different SCN5A mutations are associated with other cardiac abnormalities including Brugada syndrome, congenital long QT syndrome type 3, familial AV block, and familial dilated cardiomyopathy with conduction defects and susceptibility to atrial fibrillation (AF). [12]

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