Infantile cerebellar retinal degeneration is a rare

hereditary Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic inform ...

neurological disorder which primarily affects the eyes and the brain.

Presentation

Babies with this condition usually appear normal at birth, but start showing symptoms when they are just 6 months old, these symptoms are (but are not limited to):

hypotonia Hypotonia is a state of low muscle tone (the amount of tension or resistance to stretch in a muscle), often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases a ...

, developmental delays,

seizures An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...

, bobbing of the head, abnormal twitching and movement of the muscles, and loss of braincells from the

cerebellum The cerebellum (Latin for "little brain") is a major feature of the hindbrain of all vertebrates. Although usually smaller than the cerebrum, in some animals such as the mormyrid fishes it may be as large as or even larger. In humans, the cerebel ...

, retinal degeneration, involuntary rapid movement of the eyes, and

strabismus Strabismus is a vision disorder in which the eyes do not properly align with each other when looking at an object. The eye that is focused on an object can alternate. The condition may be present occasionally or constantly. If present during a ...

Causes

This condition is caused by mutations in the

ACO2 Aconitase 2, mitochondrial is a protein that in humans is encoded by the ACO2 gene. Structure The secondary structure of ACO2 consists of numerous alternating alpha helices and beta sheets (SCOP classification: α/β alternating). The tertiary st ...

gene, located on chromosome 22q13.2, these mutations are inherited in an autosomal recessive fashion, meaning that if both parents carry one copy of the disease-causing mutation, there is a 25% (1 in 4) chance their children will develop the disease. Normally, this gene produces a protein/enzyme that catalyzes the interconversion of citrate to isocitrate via cis-aconitate in the second step of the TCA cycle.

Etiology

The first case report of this disorder was in 2012, when affected 8 members from 2

Arab The Arabs (singular: Arab; singular ar, عَرَبِيٌّ, DIN 31635: , , plural ar, عَرَب, DIN 31635: , Arabic pronunciation: ), also known as the Arab people, are an ethnic group mainly inhabiting the Arab world in Western Asia, ...

Muslim Muslims ( ar, المسلمون, , ) are people who adhere to Islam, a monotheistic religion belonging to the Abrahamic tradition. They consider the Quran, the foundational religious text of Islam, to be the verbatim word of the God of Abrah ...

families, most of the patients were brought to the doctor when they were between 2 and 6 months of age, with most of the symptoms described before. Since then, 6 more case reports (including more than one person) reporting new cases and/or studying the disease have been documented, leaving us with a total of 26 people with the disease recorded in global medical literature.

References

{{reflist Genetic diseases and disorders Ophthalmology Autosomal recessive disorders