Neurodegeneration with Brain Iron Accumulation (NBIA)

NBIA is a group of inherited (hereditary) diseases of the central nervous system, whose common main characteristic is usually bilateral, abnormal iron deposition in the basal ganglia.

The basal ganglia are an accumulation of nuclear structures deep in the brain whose functions include the control of targeted movements and muscle tension as well as motor memory. NBIA belongs to the group of neurodegenerative diseases in which there are slow changes in nerve cells in the brain and impairments of their function, which ultimately lead to cell death.

Course and prognosis

Clinical picture

Clinically, all NBIA diseases are characterized in particular by progressive movement disorders. These are often accompanied by developmental delays, neuropsychiatric abnormalities and mental (cognitive) impairments. In addition, visual function, speech and swallowing may be impaired. Symptoms and disease progression are to a large extent dependent on the respective genetically determined NBIA subtype and can also be individually very differently pronounced.

Course

All forms of NBIA are progressive and there is currently no cure. In principle, NBIA can occur at any age, but most NBIA diseases begin in childhood or adolescence. The course is individually different, can be fast or slow, sometimes with long phases of stability and short phases of rapid deterioration. Like symptoms, the course can vary greatly from case to case, depending on which gene is mutated, i.e. which NBIA form is present.

Genetics

Different mutations within a gene can also lead to a more or less severe clinical picture. Other factors that may influence the severity and progression of the disease are not yet known.

If brothers and sisters are affected by the same NBIA disease, they will usually suffer from it at about the same age. However, the course of the disease can vary in speed of development.

PKAN – Nic’s type of NBIA
Pantothenate kinase-associated neurodegeneration

Start in the 1st decade, often before 6 years of age: classic PKAN, usually rapid;
start in the 2nd decade or later: atypical PKAN, often much slower;
PKAN often intermittent with long phases of clinically stable condition and short phases of rapid deterioration.

Classic PKAN

Clinical appearance:
Initially, fine motor, balance and gait disorders with a tendency to fall, pronounced dystonia, often generalised torsion dystonia with overstretching of the trunk (opisthotonus) and/or cervical and oromandibular dystonia, usually accompanied by spasticity, chorea, bradykinesia, rigidity, speech and swallowing disorders, possibly retinopathy pigmentosa (RP), eye motility disorders and limited cognition.

Atypical PKAN

Clinical appearance:
Initially often speech disorders, e.g. with palilalia (repeated words), neuropsychiatric abnormalities such as impulsivity, mood swings, obsessive-compulsive disorders, later dystonia Parkinsonism, spasticity, tics, less frequent eye involvement and limitation of cognition.

Hybrid forms

Clinical appearance:
Many patients cannot be clearly assigned to one of these two courses, in which symptoms from both forms occur in combination.

TOP