ico-neurogenetica

Neurogenetics

Hereditary neurological disorders

Request an appointment

Neurogenetics is a discipline that covers hereditary neurological disorders, as well as the study of the molecular basis of the nervous system.

Many neurogenetic diseases are disabling and chronic conditions and have been classed as rare diseases since they are not very common, (less than 5 cases per 10,000 citizens), according to EU standards.

It is estimated that, in Spain, around 2 million people could be suffering from a neurological disease with genetic causes, among which we have various types of Spinocerebellar Ataxias, Charcot Marie Tooth, spastic paraplegia, muscular dystrophy and myopathy, Parkinson’s and dystonia, meaning that early diagnosis is crucial, both for deciding on the best treatment and for avoiding the transmission of a genetic disease on to children.

Movement disorders are characterised by slow movements (akinesia) or by an excess of movement or abnormal and involuntary movement (dyskinesia).

Ataxias

Hereditary ataxias are a heterogeneous group of neurological diseases, characterised by imbalance, lack of coordination when walking, lack of coordination in the limbs, including the hands, dysarthria and movement disorders in the eyes.

The prevalence varies a lot between different countries from 1/50,000 for Friedreich’s Ataxia (FRD1) in Europe, to 1/100,000 for Ataxia Telangiectasia (AT) and 3/100,000 for dominant Spinocerebellar Ataxias in Holland. X-linked ataxias are rare.

Hereditary ataxias can be causes by dysfunction in the cerebellum and associated systems, lesions to the spinal medulla and/or the loss of peripheral vision.

Parkinson’s

Parkinson’s Disease (PD) is the second most common neurodegenerative disease. Approximately 1-2% of people above the age of 65 are affected by PD and this increases to 4% for those over 85. It is characterised by trembling, muscular rigidity and bardykinesia. The psychiatric expressions include depression and visual hallucinations that are not always present, as well as dementia being present in at least 20% of cases. It is believed that people suffer from it before the age of 20 have the juvenile form, those that have it before 50 are deemed to have early onset disease and those who start after the age of 50 are deemed to have late onset Parkinson’s.

Dyskinesia

These are hyperkinetic diseases and are characterised by an excess of abnormal and involuntary movements, including trembling, dystonia, chorea, ballismus, atheosis, twitches, myoclonus, hyperekplexia, hemifacial spasm, stereotypies, akathisia and other movement disorders.

Muscular disorders

This is the most common hereditary neuropathology in Spain, with a rate of 28.2 cases per 100,000 citizens. This is a syndrome with infantile or juvenile onset and is accompanied by motor and sensory polyneuropathy, pes cavus and is characterised by progressive weakness in the distal muscles of the feet and/or hands, weak dorsal flexion of the ankle, thin distal muscles, lowered tendon reflexes and the loss of distal senses.

Other pathologies including neuropathy are: Brachial plexus neuropathy, neuropathy with paralysis due to pressure, motor and/or sensory neuropathies, among others.

Congenital myasthenic syndromes (CMS)

These are caused by neuromuscular junction disorders. CSM is characterised by weakness and fatigue in the skeletal muscles, especially the ocular, bulbar and limb muscles. The clinical expressions generally appear during the neonatal period but they may start later on in childhood, adolescence or during adulthood. The severity and the process of the disease vary greatly and can range from mild symptoms to progressive and disabling weakness. In some subtypes of CMS, myasthenic symptoms can be mild but there can also be severe sudden exacerbations or even sudden episodes of respiratory failure brought about by fever, infections or nervousness. The rate is estimated at around 1-2/500,000, making up for a tenth of Miastenia Gravis cases, which account for 25 to 125 /1,000,000.

Hereditary myopathies

This is a very wide group of hereditary pathologies, especially those that are found in the neonatal period or early childhood. The phenotype of these patients include hypotonia, motor delays and there can be persistent hyperCKemia. Until now, histopathological diagnosis via biopsy was the only diagnosis mechanism. The arrival of Next-Generation Sequencing has opened the door to more efficient diagnosis for patients taking part in clinical trials.

Hereditary spastic paraplegias (HSPs) are clinical disorders that are genetically heterogeneous, characterised by spasticity and weakens in the lower limbs (occurring in variable proportion). When symptoms start after infancy, they generally progress slowly and constantly. When symptoms start during very early childhood, they may not be progressive and could appear to be spastic cerebral palsy.

HSP is classified as “uncomplicated” if the neurological deterioration is limited to spastic weakness of the lower limbs, hypertonic bladder and a slight reduction of vibratory sensation in the lower limbs. It could be “complicated HSP” if, apart from the “uncomplicated” characteristics, it is also associated with ataxia, convulsions, cognitive impairment, amiotrofia, extrapyramidal symptoms or peripheral neuropathy. We are currently aware of 70 genes associated with this pathology.

If the medical specialisation that you’re looking for is not shown here, get in contact with us and we’ll give you the specific response necessary for your case.

Here at Sistemas Genómicos, we cover the widest range of specialisations and we are constantly updating them.