Prenatal diagnosis of tuberous sclerosis: the use of fetal echocardiography

Fetal cardiac rhabdomyomas treated with maternal sirolimus

OBJECTIVE

To review the pathophysiology of rhabdomyomas and the emerging option of prenatal treatment of fetal cardiac rhabdomyomas.

METHODS

We present a case of fetal rhabdomyomas causing significant hemodynamic compromise that received in utero treatment of maternal sirolimus. Genetic amniocentesis confirmed a TSC2 mutation. A treatment program was initiated with a 10-mg loading dose titrated to a goal maternal trough of 10 to 15 ng/dL. In order to follow fetal cardiac function, a sophisticated method of speckle tracking echocardiography was used before and after treatment. Obstetric ultrasound was used to monitor fetal growth, and clinical surveillance, echocardiography, and brain MRI were used to monitor postnatal growth and development through 6 months of neonatal life.

RESULTS

Sirolimus was initiated from 28 to 36 weeks of gestation with improvement of cardiac status. During this period, intrauterine growth restriction developed. Postnatally, the infant has had stable rhabdomyomas and cardiac function without reinitiating sirolimus. Brain MRI demonstrated scattered cortical tubers and subependymal nodules, and the infant has not had seizure-like activity. At 6 months of age, the infant has achieved appropriate developmental milestones.

CONCLUSION

In counseling cases of prenatal onset large obstructing rhabdomyomas and cardiac compromise, in utero sirolimus treatment can be considered.

Multiple cardiac rhabdomyomas in tuberous sclerosis complex: case report and review of the literature

Cardiac rhabdomyoma is a benign tumor which constitutes the most common cardiovascular feature of the tuberous sclerosis complex, a multisystem genetically determined neurocutaneous disorder. Cardiac rhabdomyomas can be detected in the prenatal ultrasound, are usually asymptomatic and spontaneously regress within the first three years of life. Less often, the tumors' size, number, and location can produce a mass effect that may lead to blood flow abnormalities or organ dysfunction (heart failure and arrhythmia). In this setting, severe morbidity, and eventually, a lethal outcome despite clinical and surgical treatment may ensue. We describe a fatal case of multiple cardiac rhabdomyomas in a newborn girl. One of the rhabdomyomas was large and unfavorably located, causing significant obstruction of the left ventricular outflow tract. The autopsy identified, in addition to cardiac rhabdomyomas, brain glioneuronal hamartomas (cortical tubers), subependymal nodules and subependymal giant cell tumors, characteristic of the tuberous sclerosis complex. The newborn's family was investigated for the presence of typical clinical symptoms of the complex and image findings showed significant phenotypical variations and a broad symptom spectrum among the family members. This interesting case underscores the variability of tuberous sclerosis complex and the importance of performing a comprehensive postmortem examination in the identification of the cause of death, especially in the setting of familial disease.

Precise prenatal diagnosis of tuberous sclerosis by sequencing the TSC2 gene

BACKGROUND

The presumptive prenatal diagnosis of tuberous sclerosis (TSC) previously depended upon fetal imaging. Cloning of the two TSC genes (TSC1 and TSC2) now enables precise molecular diagnosis by gene sequencing. We used this approach for the prenatal diagnosis of a fetus showing multiple intracardiac tumors.

METHODS

DNA extracted from cultivated amniotic fluid cells underwent sequencing of all coding regions and exon-intron boundaries of the TSC1 and TSC2 genes.

RESULTS

A mutation (R611Q) was found in exon 16 of the TSC2 gene. Thus far, neither clinically unaffected parents has provided blood samples for mutation analysis.

CONCLUSION

For the first time, mutation analysis of a TSC gene enabled a precise prenatal diagnosis.

Fetal and neonatal cardiac tumors

Primary tumors of the heart are uncommon in the fetus and neonate. Nevertheless, the widespread use of new imaging techniques has contributed significantly to earlier diagnosis, treatment, and thus improved survival. The clinical findings, imaging studies, pathology, and outcome of 224 fetuses and neonates with cardiac tumors collected from the literature are evaluated and discussed. Most tumors are benign, and of these rhabdomyoma is the most common, followed by teratoma, fibroma, oncocytic cardiomyopathy, vascular tumors, and myxoma. Malignant and metastatic tumors are described but are rare. Murmurs, arrhythmias, cyanosis, respiratory distress, and cardiac failure are the main presenting signs of cardiac tumors in the perinatal period. Disturbances in hemodynamic function are correlated with the size and location of the tumor. Cardiac vascular tumors have the best outcome, whereas malignant tumors have the worst. The purpose of this review is to concentrate on the fetus and neonate in an attempt to determine the various ways cardiac tumors differ clinically and morphologically in this age group from those occurring in older children and adults and to show that certain types of tumors have a better prognosis than others.

Tuberous sclerosis with intracardiac rhabdomyoma in a fetus with trisomy 21: case report and review of literature

A large cardiac rhabdomyoma protruding into the left ventricle was diagnosed in a fetus at 21+2 weeks of gestation by grey-scale echocardiography. Obstruction to left ventricular outflow was ruled out by colour and spectral Doppler echocardiography. No other abnormalities were noted and karyotyping by cordocentesis revealed trisomy 21 (47,XY,+21). Post-mortem examination after termination of pregnancy confirmed the prenatal diagnosis of cardiac rhabdomyoma and in addition revealed fetal tuberous sclerosis. Demonstration of cardiac rhabdomyoma by prenatal ultrasound should raise suspicion of the presence of fetal tuberous sclerosis. Despite the incidental association with aneuploidy, fetal karyotyping is suggested for optimal counselling of parents.

Hydrops fetalis: role of the geneticist

The causes of hydrops fetalis are myriad. As a result of the advent of routine Rh screening, most cases are not currently related to Rh incompatibility. Genetic, metabolic, chromosomal, and syndromic causes are among the most frequently identified causes of nonimmune hydrops. The importance of determining the underlying cause of hydrops becomes evident once issues such as prognosis, specific treatment, and risk of recurrence are considered. The medical geneticist is highly qualified to assist in the evaluation of hydrops. Clinical geneticists have undergone training in a primary care specialty followed by intensive training in the diagnosis, management, and counseling of individuals and families with genetic, chromosomal, or multifactorial syndromes or birth defects. This training prepares the medical geneticist well to serve as a consultant when hydrops is diagnosed. As knowledge of the molecular genetic and metabolic basis of disease increases, utilization of genetics laboratories continues to increase dramatically. In addition to examining the child to look for dysmorphic features, the clinical geneticist can assist with the laboratory evaluation by coordinating testing with the cytogeneticist, molecular geneticist, and biochemical geneticist as appropriate. Increased awareness of the role of the geneticist in the evaluation of such patients should prove helpful to the physicians caring for such patients and the patients' families.

Cardiac involvement in tuberous sclerosis

OBJECTIVE

To assess the incidence, importance, and history of cardiac involvement in infants and children with tuberous sclerosis.

DESIGN

Prospective study; clinical examination, sector and Doppler echocardiography, standard and ambulatory electrocardiography.

SETTING

A tertiary referral centre.

PATIENTS

21 patients with tuberous sclerosis aged 1 day to 16 years (mean 6.3 years); follow up investigations were available in 14 cases (10 retrospective, 4 prospective; mean follow up 4.3 years).

RESULTS

Multiple cardiac rhabdomyomas in the right ventricle (11) and left ventricle (14) as well as in the right atrium (1) were present in 14/21 patients. Two of them had obstruction of the left ventricular inflow and outflow tract related to a tumour. In the remaining 7 patients, echocardiography was normal in 4 and equivocal in 3 cases. The standard electrocardiogram (n = 20) showed ventricular hypertrophy (2), ventricular pre-excitation (1), arrhythmias (2), and repolarisation disturbances (4) in 7/13 patients with rhabdomyomas but was normal in all patients with a normal or equivocal echocardiogram. The ambulatory electrocardiogram (n = 19) showed frequent premature atrial (2) and polymorphous ventricular (2) contractions. The polymorphous ventricular contractions coexisted with rhabdomyomas. No arrhythmias that needed medical treatment were found. Follow up investigations showed return to a normal standard electrocardiogram in 3 patients. Definite regression or complete disappearance of the tumour occurred in 6 infants.

CONCLUSIONS

Cardiac rhabdomyomas, although often present in these patients with tuberous sclerosis, caused neither major arrhythmias nor haemodynamic obstruction except in the neonatal period. The indication for operation is limited to cases with life threatening obstruction or arrhythmias refractory to medical treatment.

Prenatal diagnosis of tuberous sclerosis. Use of magnetic resonance imaging and its implications for prognosis

Tuberous sclerosis (TS) is an autosomal dominant disorder with a high rate of de novo mutation. The real difficulty is to ascertain the diagnosis and to give the neurological prognosis in each case. Prenatal diagnosis of TS is generally based on ultrasonographic signs of multiple cardiac tumours, i.e. rhabdomyomas. Recent progress in magnetic resonance imaging (MRI) enables the diagnosis in a large proportion of cases based on typical brain lesions. It may have a role in the prenatal management of TS, although MRI images seem to underestimate the anatomical findings. Two cases in which TS was diagnosed prenatally are presented with reference to the value of MRI in the prenatal management and comparison with anatomical findings.

A fetal cystic neck mass associated with maternal tuberous sclerosis. Case report and literature review

Tuberous sclerosis is a single gene autosomal-dominant disorder, characterized by multiple hamartoma formation. It shows a wide variability of expression. Prenatal diagnosis by means of a DNA or biochemical marker is not yet possible. Ultrasound offers the only way to detect possible antenatal hamartoma formation, which is most commonly found in the central nervous system, the renal system, and the heart. We report a case of fetal involvement that appears unique because of the unusual location of a tumour in the neck of the fetus.

Tuberous sclerosis presenting with fetal and neonatal cardiac tumours

Cardiac tumours were identified on ultrasonography in fetal or early postnatal life in five infants. Tuberous sclerosis was subsequently diagnosed in all five. Only one infant required operation. Regression of the tumour occurred in three. No infant had hypomelanotic macules at birth, and they took up to two years to appear.

Hydrops revisited: literature review of 1,414 cases published in the 1980s

This paper reviews 47 series of hydrops fetalis (804 cases) and 610 individual cases published since 1980. From this large number of cases, guidelines are derived for prenatal diagnosis and management.

Role of prenatal detection of cardiac tumours in the diagnosis of tuberous sclerosis--report of two cases

Tuberous sclerosis is an autosomal dominant disease with variable expression. Little is known about the intrauterine course of the disease and the fetal age at which specific abnormalities may be detected. The role of prenatal detection of cardiac tumours in the diagnosis of two fetuses at 28 and 32 weeks' gestation based on fetal echocardiography is discussed. The prenatal and postnatal course of the disease is described.