Top 4 Most Common Hereditary Neurological Disorders in Children
Heredity Neurological Disorders (HNDs) are slightly common in children in comparison to adults. A clinical manifestation of HNDs is important to recognize for selection of genetic testing, consultation and testing results interpretation. The advanced in-next generation sequencing testing technology has enabled us to identify the genetic causes of heredity neurological disorders. It further eases the challenges paediatricians face while applying genetic investigation. The combination of advanced technologies and clinical information further enhances the genetic test yields in clinical settings.
Here in this article, we are going to focus on genetic causes of neurological disorders in major areas like movement disorders, neuropsychiatric disorders, epilepsy and neuron peripheral disorders. The near future foresees an empowering transition from research-based use of comprehensive genetic testing of HNDs to their clinical use.
Heredity neurological disorders are significantly common in paediatric neurological practice. HNDs are a group of genetic diseases, most of which have a Mendelian inheritance affecting neurological systems. HNDs can occur at any age, but the initial symptoms of it can be seen in childhood and congregate in a certain age group. Congenital malformation if present can be identified during preterm and postneonatal periods.
In most HNDs there are various means to guide clinical classifications:
- The early clinical signs refer to one neuro-anatomical region or pathology specific of that region
- The on-set age of clinical signs and symptoms
- Mode of inheritance
- Extra neural signs and symptoms such as the presence of specific signs involving skin, eyes, connective tissues or visceral organs
The aim of HND diagnosis is gene diagnosis, although neuro-imaging, biochemical analysis of body fluids can also assist in finding an accurate diagnosis. Just as a set of clinical features that can result from mutations in different genes, single-gene mutations can manifest with different clinical phenotypes. The similar gene mutations that cause a different clinical phenotype, indicates the presence of genetic and environmental modifiers, and similar therapeutic approaches can be employed in the spectrum of HNDs which are caused by a single gene.
- Paediatric Heredity Movement Disorders
Huntington disease (HD) is the most significant genetic cause of abnormal cerebellar symptoms and involuntary writhing movements. Cognitive decline to speech, language delay, psychiatric problems and rapid decline often occur. Epileptic seizures are unique to the youngest onset group and present in 30-50% of those with an onset of HD before the age of ten years. In teenagers, symptoms are very similar to adult HD with the characteristic chorea.
- Genetics of Development and Neuropsychiatric Disorders
Neuropsychiatric disorders include an array of clinical features, such as intellectual disability, developmental delay, autism spectrum disorders and cognitive dysfunctions etc. Various intellectual developmental disorders like attention deficit hyperactivity disorder are caused due to complex genetic contribution like complication during pregnancy or birth, environmental factors, etc.
Autism spectrum disorders are characterized by varying degrees of limitations in communication, social interaction and atypical repetitive behaviours before the age of three years. For assuring an accurate diagnosis of autism, a genetic investigation is highly important for achieving a high genetic diagnostic yield. ASDs are complex disorders, approximately 20-30% of patients of ASD with an existing family history of developmental disability or psychiatric problems have multiple genes copy-number variants.
- Genetics of Hereditary Neuron Peripheral Disorders
Spinal muscular atrophies (SMAs), a group disorder of lower motor neurons degeneration affect the anterior horn of the spinal cord which leads to neuronal death. SMAs are caused by deletions/mutations in multiple genes, such as UBA1, SMN1, ATP7A, IGHMBP2, etc. Clinically, SMAs have numerous presentations with different disease and progressions and onset ages. The most common affected gene is the deletion of the axons 7 and 8 of the SMN1 gene with a carrier frequency of 1 in 40 in Caucasians.
Mitochondrial diseases (MIDs), a group of systematic disorders, which are caused by defects in the mitochondrial genome, are purely inherited from the mother. A common cause of MIDs is the deficiency in nuclear genes encoding the mitochondrial protein. The characteristic signs of children with MIDs are loss of muscle coordination and muscle weakness. Other clinical features, like slow growth, seizures, learning disabilities, dementia, and multi-organs dysfunction can also be present.
- Genetics of Epilepsy
Inherited epilepsy syndromes can be classified based on the genetic contribution to the aetiology as monogenic epilepsies and complex epilepsies. Together with the complex genetic contribution, environmental factors also have a major role in epilepsy occurrence. Thus, heterogeneous clinical presentations of epilepsy can often be seen in clinics.
There are stroke doctors who can help in an accurate diagnosis of heredity neurological disorders. It is highly advised to visit any highly experienced neuro specialist in Delhi NCR or nearby you if you’re facing any of the above-stated symptoms.