Oculocerebrofacial Kaufman syndrome ... (oculocerebrofacial Kaufman syndrome) - Gen UBE3B  

Oculocerebrofacial Kaufman syndrome is a condition characterized by eye problems, intellectual disabilities and a distinctive pattern of facial features.

Most individuals with oculocerebrofacial Kaufman syndrome have microcephaly, and some have structural brain abnormalities. Affected individuals suffer from hypotonia and show a delayed development of motor skills. Intellectual disability is often severe, so that most affected individuals never acquire the ability to speak. Ocular abnormalities and their effect on vision varies between individuals with oculocerebrofacial Kaufman syndrome. These abnormalities may include microphthalmia, microcornea, coloboma, optic nerve hypoplasia, strabismus and myopia or hyperopia and Entropion. The characteristic pattern of facial features in these individuals is characterized by very eyebrows, telecanthus, blepharophimosis, epicanthal folds, drooping eyelids and palpebral fissures upward; set ears with small lobes and skin growths front of the ear; narrow nasal bridge with wide base and nostrils to the front instead of down, flat cheeks, unusually long and flat philtrum, narrow mouth and micrognathia.

Other signs and symptoms may include additional short stature; hearing loss; and cardiac abnormalities, respiratory tract, gastrointestinal tract, kidney, skeletal or genitals. Although affected individuals can live into adulthood, their average life expectancy is unknown because of the small number of people who have been diagnosed with this syndrome.

This process is due to mutations UBE3B gene (ubiquitin ligase E3B protein), located on the long arm of chromosome 12 (12q24.11), encoding a protein that plays a role in the ubiquitin-proteasome system. The ubiquitin-proteasome system acts as quality control system of the cell by removing damaged proteins, and deformed excessively. This system also regulates the concentration of proteins involved in several critical cellular activities such as the time of cell division and growth. Tagged proteins by complex involving UBE3B protein is unknown, but studies indicate that the protein acts on the nervous system, gastrointestinal tract, respiratory system and other organs and tissues, before birth to adulthood.

They have identified at least 15 UBE3B gene mutations in people with oculocerebrofacial Kaufman syndrome. It is believed that the associated mutations result in abnormal protein UBE3B may not operate properly or it is unstable and rapidly decomposes. The loss of function of this protein probably prevents cells eliminate certain unnecessary proteins, leading to problems with the development and function of the nervous system and other body parts.

This disease is inherited in an autosomal recessive pattern, which means that both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with oculocerebrofacial Kaufman syndrome, by complete PCR amplification of exons UBE3B gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).