Maternal auto-immune diseases:
(1) systemic lupus erythematosus
(2) primary Sjogren's syndrome
(3) undifferentiated connective tissue disease
Antibodies involved:
(1) anti-Ro/SSA (anti-52-kd more likely to have heart block than anti-60-kd)
(2) anti-La/SSB
Clinical findings in affected infants:
(1) cardiac
(1a) congenital complete heart block (may be detected as early as 20 weeks gestation)
(1b) sinus braydcardia (usually transient)
(1c) prolonged QT interval
(2) hemolytic anemia and/or thrombocytopenia
(3) skin rash, often photosensitive
(4) hepatomegaly with elevated liver function tests and cholestasis
Other interesting findings:
(1) The history of a previous infant with complete heart block is a major risk factor for a mother having an infant with congenital complete heart block.
(2) Many women with affected infants are asymptomatic or oligosymptomatic at the time of delivery. It is only after delivery of an affected infant that the mother is identified as having an autoimmune disease.
(3) In the study of Brucato et al, only 2% of infants with anti-Ro/SSA developed complete heart block. None of these were born to women with recognized SLE; SLE is more likely to have the anti-60-kd form of anti-Ro/SSA.
(4) The complete heart block appears to follow a myocarditis.
(5) Most infants have transient symptoms but some may have long term permanent damage. Infants with complete heart block may require insertion of a pacemaker.
