Familial atrial septal defect with prolonged atrioventricular conduction

Risk and protective factors in the origin of atrial septal defect secundum--national population-based case-control study

The aim of this study was to assess the risk factors in the origin of lethal or surgically corrected isolated atrial septal defect secundum. The population-based Hungarian Case-Control Surveillance of Congenital Abnormalities (conducted between 1980 and 1996) comprised 472 atrial septal defect secundum cases, 678 matched controls and 38,151 available controls without any defects; in addition, 21,022 malformed controls with other isolated defects. Medically recorded chronic disorders in the prenatal maternity logbook were evaluated, while acute maternal diseases, drug treatments and pregnancy supplements were analyzed on the basis of both prospective medically recorded data and retrospective maternal information. Acute pelvic inflammatory disease, paroxysmal supraventricular tachycardia and phenolphthalein treatment due to severe constipation of mothers were shown to contribute to the development of atrial septal defect secundum of their children. High doses of folic acid in early pregnancy had positively influenced a minor part of isolated atrial septal defect secundum in foetuses. In conclusion, the obvious genetic predisposition for atrial septal defect secundum is connected with maternal paroxysmal supraventricular tachycardia and triggered by acute pelvic inflammatory diseases and phenolphthalein treatment, while the manifestation of atrial septal defect secundum can be reduced by high doses of folic acid supplementation in early pregnancy.

The familial form of atrial septal defect

BACKGROUND

The secundum atrial septal defect accounts for 10% of congenital heart disease. Familial occurrence is rare and may present as an isolated lesion or with conduction and skeletal abnormalities. Predisposing genes were described.

OBJECTIVES

To evaluate familial defect's prevalence and associated anomalies and assess the yield of screening.

METHODS

Family history, physical, electrocardiographic and echocardiographic evaluation of 286 ASD patients and families regarding heart disease, conduction and skeletal anomalies were performed.

RESULTS

Eleven new families with familial defects were identified yielding 28 patients. The rate of transmission was 40-100%, suggestive of autosomal dominant inheritance. Parents were healthy in four families with multiple offspring with ASDs. Two families had ASDs with atrioventricular conduction abnormalities in five of six subjects, not requiring pacing. One subject had skeletal malformation. Ten patients had surgery, 12 had transcatheter ASD closure and six await treatment.

CONCLUSIONS

In view of the high prevalence of familial occurrence of secundum ASD (10% of all ASD patients), we recommend screening all first degree relatives of ASD patients for cardiac, conduction and skeletal anomalies. Although a routine genetic investigation is not yet available, genetic patterns of inheritance may be compatible with autosomal dominant inheritance. Healthy parents of affected offspring may suggest a variable gene penetrance or past spontaneous ASD closure. Conduction anomalies may be present or may develop throughout life, and thus should be periodically screened for.

Holt-Oram syndrome: a clinical genetic study

A clinical and genetic study of the Holt-Oram syndrome (HOS) has been carried out in the United Kingdom involving 55 cases designated Holt-Oram syndrome, together with their parents and sibs. Data from the clinical assessment of both familial and isolated cases were used to define the HOS phenotype and to outline the spectrum of abnormalities, especially factors affecting severity. Skeletal defects affected the upper limbs exclusively and were bilateral and asymmetrical. They ranged from minor signs such as clinodactyly, limited supination, and sloping shoulders to severe reduction deformities of the upper arm (4.5%). The radial ray was predominantly affected than the right. All affected cases showed evidence of upper limb involvement. Cardiac defects were seen in 95% of familial cases and included both atrial septal defect (ASD, 34%) and ventricular septal defect (VSD, 25%); 39% had only ECG changes. Cardiac involvement ranged from asymptomatic conduction disturbances to multiple structural defects requiring surgery in infancy. Sudden death could be caused by heart block. Inheritance was autosomal dominant with 100% penetrance and no evidence of reduced fitness. Increasing severity occurred in succeeding generations consistent with anticipation.