Prenatal diagnosis of tuberous sclerosis with intracerebral signs at 14 weeks' gestation

Fetal Bradycardia Caused by Monogenic Disorders-A Review of the Literature

Introduction: The standard obstetric definition of fetal bradycardia is a sustained fetal heart rate < 110 bpm over at least 10 min. Fetal bradycardia can be the first and only prenatal presentation of a heart disease. We present an overview on different genetic disorders that should be taken into consideration in case of diagnosed fetal bradycardia. Methods: A literature review was conducted using a PubMed- and OMIM-based search for monogenetic disorders causing fetal bradycardia in September 2022. Results: The review on the literature identified nine monogenic diseases that could lead to fetal bradycardia. Four of these disorders can be associated with extracardiac findings. Discussion: Genetic testing should be considered in cases with fetal bradycardia, especially in cases of additional extracardiac findings. Broad sequencing techniques and improved prenatal phenotyping could help to establish a diagnosis in an increasing number of cases.

Prenatal MR Imaging Phenotype of Fetuses with Tuberous Sclerosis: An Institutional Case Series and Literature Review

BACKGROUND AND PURPOSE

Most patients with tuberous sclerosis complex (TSC) do not receive prenatal diagnosis. Our aim was to describe MR imaging findings to determine the following: 1. Whether normal fetal MR imaging is more common in fetuses imaged at ≤24 weeks' gestation compared with >24 weeks 2. The frequency of cardiac rhabdomyoma 3. The range of MR imaging phenotypes in fetal tuberous sclerosis complex.

MATERIALS AND METHODS

Our institutional fetal MR imaging data base was searched between January 1, 2011 and June 30, 2021, for cases of TSC confirmed either by genetic testing, postnatal imaging, postmortem examination, or composite prenatal imaging findings and family history. A MEDLINE search was performed on June 8, 2021.

RESULTS

Forty-seven published cases and 4 of our own cases were identified. Normal findings on fetal MR imaging were seen at a lower gestational age (mean, 24.7 [SD, 4.5 ] weeks) than abnormal findings on MR imaging (mean, 30.0 [SD, 5.3] weeks) (P = .008). Nine of 42 patients with abnormal MR imaging findings were ≤24 weeks' gestation. Subependymal nodules were present in 26/45 cases (57.8%), and cortical/subcortical lesions, in 17/46 (37.0%). A foramen of Monro nodule was present in 15 cases; in 2/7 cases in which this was unilateral, it was the only abnormal cerebral finding. Cardiac rhabdomyoma was absent in 3/48 cases at the time of fetal MR imaging but was discovered later. Megalencephaly or hemimegalencephaly was observed in 3 cases.

CONCLUSIONS

Fetuses with abnormal cranial MR imaging findings were older than those with negative findings. Fetal hemimegalencephaly and megalencephaly should prompt fetal echocardiography. Cardiac rhabdomyoma was not always present at the time of fetal MR imaging.

Value of fetal cerebral MRI in sonographically proven cardiac rhabdomyoma

BACKGROUND

Tuberous sclerosis complex (TSC) is an autosomal dominant phakomatosis associated with intracardiac rhabdomyomas.

OBJECTIVE

The aim of our study was to examine the value of cerebral MRI in diagnosing TSC in fetuses with intracardiac rhabdomyomas, applying the TSC Consensus Conference (TSCCC) criteria.

MATERIALS AND METHODS

In a prospective manner six consecutive fetuses with cardiac rhabdomyomas (21-34 weeks' gestation) underwent cerebral MRI. The MRI results were correlated with clinical follow-up at 10-34 months after birth, histology, and genetic data.

RESULTS

In five of the six fetuses the diagnosis of TSC was established. In two of five fetuses MRI demonstrated cerebral manifestations of TSC that correlated well with severe epilepsy manifesting during the follow-up period. In another two of five fetuses MRI as well as clinical follow-up were normal. One of five pregnancies was terminated and histology demonstrated microscopically small subependymal nodules not demonstrated by MRI.

CONCLUSION

The results of our study agree with the available literature that fetal MRI is sufficient for the detection of cerebral lesions in TSC and should be better promoted. The TSCCC criteria can also be applied to fetal MRI.

Cancer genetic testing and assisted reproduction

PURPOSE

Because of increasing uptake of cancer genetic testing and the improving survival of young patients with cancer, health care practitioners including oncologists will increasingly be asked about options for assisted reproduction by members of families affected by hereditary cancer syndromes. Among these reproductive options, preimplantation genetic diagnosis (PGD) offers the opportunity to select embryos without familial cancer-predisposing mutations.

METHODS

A review of the published literature supplemented by a survey of PGD centers in the United States.

RESULTS

Prenatal diagnosis and/or embryo selection after genetic testing has already been performed in the context of more than a dozen familial cancer syndromes, including the common syndromes of genetic predisposition to colon and breast cancer.

CONCLUSION

While constituting new reproductive options for families affected by cancer, the medical indications and ethical acceptance of assisted reproductive technologies for adult-onset cancer predisposition syndromes remain to be defined. Continued discussion of the role of PGD in the reproductive setting is needed to inform the responsible use of these technologies to decrease the burden of heritable cancers.

Increased Brain Apparent Diffusion Coefficient in Tuberous Sclerosis

PURPOSE

To evaluate the water diffusivity of normal-appearing white matter (NAWM) in patients with tuberous sclerosis complex compared with that in control subjects.

MATERIALS AND METHODS

Diffusion and conventional magnetic resonance (MR) imaging examinations were performed in 18 patients with clinically established tuberous sclerosis complex (10 male and eight female patients; mean age, 20.1 years; range, 12-30 years), as well as in 18 age-matched control subjects (nine male and nine female; mean age, 20.2 years; range, 11-28 years). Apparent diffusion coefficients (ADCs) were generated, and small elliptic regions of interest were manually placed both in perilesional NAWM and in six anatomic locations of NAWM remote from hamartomatous lesions. Perilesional ADCs were compared with those at the same anatomic site on the contralateral side of the brain (generalized linear regression analysis). ADCs from the predetermined sites in patients were compared with those in control subjects (generalized linear regression analysis).

RESULTS

Supratentorial ADCs were higher in patients with tuberous sclerosis complex than in control subjects, and statistically significant differences were observed in the occipital white matter, frontal white matter, centrum semiovale, parietal white matter, and corona radiata (for each location, P <.001). Significant increases were also seen in the perilesional NAWM compared with NAWM at the same anatomic locations on the contralateral side (P <.001). Infratentorial ADCs were normal.

CONCLUSION

Significant ADC increases were measured in the supratentorial NAWM.

[Post mortem brain MRI: an alternative for pathology examination in Bourneville tuberous sclerosis of the fetus?]

Antenatal discovery of cardiac rhabdomyomes evokes the diagnosis of Bourneville's disease. Antenatal brain exploration with ultrasonography and magnetic resonance imaging (MRI) can highlight cerebral localizations. In the event of termination of pregnancy, confirmation of the cerebral lesions can be achieved with post mortem MRI as well as pathology examination. MRI can be usefully employed in the event pathology examination is not feasible.

Tuberous sclerosis in a 19-week fetus: immunohistochemical and molecular study of hamartin and tuberin

Tuberous sclerosis complex (TSC) is a genetically heterogeneous disease caused by mutations of TSC1 or TSC2 genes. It involves multiple organ systems resulting in mild to lethal hamartoma formation due to gene mutation in the germ line and loss of heterozygosity (LOH) in somatic cells. Hamartin (TSC1) and tuberin (TSC2) are expressed broadly. However, little is known about tissue susceptibility to hamartomas when equal or similar amounts of TSC gene expression are present. In this study, we present a 19-week gestational age fetus with pathological features of TSC, which was confirmed by finding LOH of TSC2 in a cardiac rhabdomyoma. Developmental expression of hamartin and tuberin in the TSC fetus, an age-matched non-TSC fetus, and a 26-week gestational age non-TSC fetus were analyzed by immunohistochemistry. We found that in addition to the differential expression of the TSC genes in some normal tissues compared with that in the TSC-affected fetus, the cellular localization and distribution of hamartin and tuberin were dramatically different in different tissues. In general, hamartin and tuberin are mainly expressed in epithelial cells, myocytes, and neural tissues. By comparing the incidence of the hamartomas in early childhood and gene expression in tissues, it appears that tissues with co-expression of hamartin and tuberin are prone to a higher incidence of hamartomas than those expressing only one protein, or two proteins but in different patterns of cellular localization.

Dermatologic clues to inherited disease

Genetic diseases often have cutaneous manifestations, which can be the first or most prominent signs of the underlying problem. Recognition of these dermatologic clues allows prompt diagnosis and intervention. In this article, the authors have attempted to outline several important examples of genodermatoses.