A review of neurogenetics in fetal and neonatal clinical medicine.

This review of neurogenetics serves as a primer for clinicians practicing in fetal-neonatal medicine. The review provides an update on neurogenetics, understanding the language of genetics, genetic testing approaches, and interpretation of genetic test results. Common examples of neurogenetic disease in fetal-neonatal medicine are used to enhance basic concepts.

Developmental epileptic encephalopathy in DLG4-related synaptopathy.

Objective: The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail.

Respiratory system involvement in Costello syndrome.

Costello syndrome (CS) is a multisystem disorder caused by heterozygous germline mutations in the HRAS proto-oncogene. Respiratory system complications have been reported in individuals with CS, but a comprehensive description of the full spectrum and incidence of respiratory symptoms in these patients is not available. Here, we report the clinical course of four CS patients with respiratory complications as a major cause of morbidity.

Clinical Course of Six Children With GNAO1 Mutations Causing a Severe and Distinctive Movement Disorder.

Objectives: Mutations in GNAO1 have been described in 11 patients to date. Although most of these individuals had epileptic encephalopathy, four patients had a severe movement disorder as the prominent feature. We describe the largest series of patients with de novoGNAO1 mutations who have severe chorea, developmental delay, and hypotonia in the absence of epilepsy.

An unusual cause of peroneal neuropathy.

We discuss the case of a teenage girl who presented with neurologic symptoms suggestive of a peripheral neuropathy, before the development of a central arteriovenous fistula. Electromyography and nerve conduction studies indicated peroneal motor neuropathy, but her comprehensive genetic study results were negative for common Charcot-Marie-Tooth mutations. After 2 years of stable symptoms, she presented with unilateral throbbing headache and tinnitus.