Congenital hypertrichosis, osteochondrodysplasia, and cardiomegaly: further delineation of a new genetic syndrome.

The hypertrichosis and osteochondrodysplasia syndrome is a rare entity with clinical findings including macrosomia at birth cardiomegaly. Autosomal recessive inheritance is presumed based on the report of two affected sibs born to healthy parents. Here we report on four new patients with their follow-up data, as well as on one of the four cases from the original report. Comparison of all eight cases indicates that they share 50% of clinical and radiological changes. This report contributes to the further delineation of this newly recognized syndrome.

Cardiac septal hypertrophy in hyperinsulinemic infants.

One infant with nesidioblastosis, and five of 18 infants of diabetic mothers had echocardiographically determined septal hypertrophy (greater than or equal to 6 mm). No correlation was found between the septal hypertrophy and the presence of hypocalcemia, polycythemia, birth asphyxia, or other observed clinical findings. All of the infants with septal hypertrophy, however, had profound hypoglycemia shortly after birth in contrast to those infants without septal hypertrophy. Macrosomic IDM have intrauterine hyperglycemia and hyperinsulinemia. The presence of profound neonatal hypoglycemia is consistent with the metabolic effects of significant neonatal hyperinsulinemia which is also present in the fetus. Infants with nesidioblastosis also have fetal hyperinsulinemia. Recent investigations have suggested an important role for insulin in the developing heart since it is rich in insulin receptors and contains marked insulin degrading capacity. Although fetal hyperglycemia has been suggested as the cause of septal hypertrophy in IDM, we hypothesize that fetal hyperinsulinemia contributes directly to the spinal hypertrophy.

The natural history of hypertrophic cardiomyopathy in infants of diabetic mothers.

Eleven infants of diabetic mothers with hypertrophic cardiomyopathy have been followed for 30 to 40 months. All infants presented with cardiorespiratory distress and were found to have disproportionate septal hypertrophy on echocardiogram. Cardiac catheterization was done in four infants; three had significant subaortic obstruction. One infant had remarkable improvement after treatment with propranolol. Two infants who received digoxin did poorly and responded favorably to cessation of therapy. The natural history of HCM-IDM appears to be benign, with a resolution of symptoms within two to four weeks and a resolution of septal hypertrophy within two to 12 months. Most of the infants need only supportive care; if pharmacologic intervention is deemed necessary, propranolol appears to be the drug of choice. The natural history of this entity is that of spontaneous regression of symptoms and septal hypertrophy irrespective of therapy.

Intrauterine supraventricular tachycardia.

Six examples of intrauterine supraventricular tachycardia together with 31 previously reported cases are described and analyzed. Among the 37 infants, structural heart disease was present in only four (11%), three of whom died. Males comprised 68% of the group without identifiable heart disease or pre-excitation. Congestive heart failure was evident in 62% of the infants at birth or shortly thereafter; ascites was the predominant finding in three (8%). Neither the duration of SVT nor heart rate was predictive of the clinical status at birth. Infants without underlying heart disease or conduction abnormalities had a benign course after the neonatal period. Thirty-eight percent of the babies converted to sinus rhythm during or shortly after delivery without medication, and most of the others converted after digitalization. The failure of maternal digitalization to convert SVT to sinus rhythm in two of our infants was perhaps related to subtherapeutic maternal and fetal digoxin levels. Newborn infants presenting with unexplained ascites or congestive heart failure should have an ECG to determine whether pre-excitation is present, and their cardiac rhythm should be monitored for several days.