Hypertrophic cardiomyopathy in a newborn infant

Antenatal diagnosis of pompe disease by fetal echocardiography: impact on outcome after early initiation of enzyme replacement therapy

Hypertrophic cardiomyopathy (HCM) affects most infants with Pompe disease (PD), and may serve as a marker for its antenatal diagnosis (ANDx) by fetal echocardiography (FE). Fetuses diagnosed with HCM between 2006 and 2009 were included in this study. HCM, defined as Z-score of mean left ventricular wall thickness (LVWT) and/or mass (LVM) above 2, was detected in 5/1,268 fetuses (0.39%) carried by 1,137 pregnant women referred for FE. Three fetuses (0.24%) had postnatal confirmation of PD. Their gestational age and fetal weight at diagnosis was (mean ± standard deviation) 31 ± 3.6 weeks and 1.9 ± 0.2 kg, respectively. Fetal Z-score of LVM and LVWT was 3.8 ± 0.9 and 3.1 ± 0.6, respectively. Postnatally, acid α-glucosidase (GAA) enzyme activity was nearly absent in all patients, 2 were homozygous for the mutation 1327-2A>G in the GAA gene, and 1 was homozygous for 340insT. Enzyme replacement therapy (ERT) was initiated 4.9 ± 7.8 days after birth (range 2 h-14 days), and continued every 2 weeks. Two infants are alive at 4 and 31 months, and one died of aspiration pneumonia at 19 months. Cardiac hypertrophy resolved after 10-12 weeks of ERT in all patients, and none required any respiratory support. One patient had normal neurodevelopmental assessment at 25 months, and one had severe global delay at 15 months before death. ANDx of PD by FE is feasible based on fetal HCM. It promotes early initiation of ERT which may improve outcome in some patients. However, larger studies and longer follow-ups are required.

Early administration of enzyme replacement therapy for Pompe disease: short-term follow-up results

Pompe disease (glycogen storage disease II, OMIM # 232300), is a hereditary lysosomal disorder. It is characterized by deficiency of acid alpha-glucosidase enzyme (acid maltase, GAA, OMIM *606800, EC 3.1.26.2), secondary to mutations in the GAA gene (HGNC:4065) on chromosome 17q25.2-q25.3. Absent enzyme activity in the infantile form of Pompe disease results in abnormal glycogen deposition in the skeletal, cardiac, and smooth muscles, leading to hypertrophic cardiomyopathy, feeding abnormalities, hypotonia, weakness, respiratory insufficiency, and ultimately death. Prenatal diagnosis is accomplished by enzyme assay, mutation analysis or electron microscopy of amniotic fluid cells or chorionic villus sample. However, these techniques may not always be available, and can result in perinatal morbidity and fetal loss. Early diagnosis of Pompe disease results in early institution of enzyme replacement therapy (ERT), which minimizes morbidity and prolongs survival. We report the case of a 35-week part-of-twin neonate, whose older sibling died earlier because of infantile Pompe disease. At 32 weeks of gestation, fetal echocardiography showed hypertrophic cardiomyopathy in twin 1, which persisted until birth at 35 weeks of gestation. Diagnosis was confirmed after birth by enzyme assay, and mutation analysis showing homozygosity for the sequence change 1327-2A>G (GAA intr 8). Administration of ERT at 18 h of age, resulted in normalization of cardiac abnormalities within 21 weeks of therapy, and normal neurodevelopmental assessment at 46 weeks, using Griffiths Mental Development Scales. To our knowledge, this is the youngest patient reported to receive ERT for Pompe disease, and the first report of prenatal diagnosis of Pompe disease by fetal echocardiography.

A rare presentation of Pompe disease with massive hypertrophic cardiomyopathy at birth

We report a term infant with Pompe disease presenting in the immediate newborn period. The infant was born at 40 weeks' gestation, weighing 3600 g to a 32 year-old black female. Infant presented at delivery with massive hypertrophic cardiomyopathy and pulmonary hypertension. Diagnosis was confirmed by low alpha-glucosidase activity. The histopathology and electron microscopic findings were consistent with Pompe disease. This is the second reported case of Pompe disease presenting at delivery.