Infantile neuroaxonal dystrophy 1

Infantile neuroaxonal dystrophy (INAD) 1 is a rare inherited disorder that affects the nervous system. Symptoms typically begin to appear between six months and three years of age. A baby's motor development will start out normally and then begin to slow down. The ability to walk may be delayed and then lost. Muscle control at first will be weak and floppy and then become stiff. The lack of muscle control causes breathing problems that often leads to frequent infections. Mental capacity also deteriorates to a point that children affected with INAD 1 become unaware of their surroundings. Vision and hearing loss are also common in affected children. Death usually occurs before 10 years of age, though some individuals have survived into their teens. There is no cure for INAD 1, but medical surveillance and care may help to improve some symptoms and overall condition of life. INAD 1 is caused by pathogenic variants in the PLA2G6 gene.

INAD 1 is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are generally no signs or symptoms associated with being a carrier for INAD 1. However, the risk to have a child affected with INAD 1 is increased. Testing of reproductive partners is recommended for carriers of INAD 1.

It is unknown exactly how often INAD 1 occurs.

The following websites may be informative: Genetic Home Reference: Infantile neuroaxonal dystrophy (http://ghr.nlm.nih.gov/)($) National Institute of Neurological Disorders and Stroke: Infantile neuroaxonal dystrophy (www.ninds.nih.gov/)

Gene Reviews: PLA2G6-Associated Neurodegeneration (http://www.ncbi.nlm.nih.gov/books/NBK1116/) OMIM: [309000: 256600: INFANTILE NEUROAXONAL DYSTROPHY 1] (http://www.ncbi.nlm.nih.gov/omim)

• Full gene sequencing