Mucolipidosis is a disease that causes high levels of fats and carbohydrates to build up in the body's cells. The cells are not able to handle such high amounts of these substances, so they become damaged over time. Children born with mucolipidosis sometimes show symptoms of the disease at birth, but some don't display signs early childhood. The most common symptoms include physical deformities as well as mental retardation or learning disabilities.
In order for a child to be born with mucolipidosis, the child must inherit a defective gene from each parent. A child who inherits only one mutated gene from either the mother or the father is a carrier but will not suffer from the symptoms of the disease. Expectant parents often undergo genetic testing before their babies are born to identify whether one or both of them are carriers of the disease. If only one parent is a carrier, the child will not be born with the disease since babies inherit one gene from each parent. Genetic testing cannot identify every type of mutation that could lead to mucolipidosis, but it can often identify the most common types.
Mucolipidosis is broken down into four types. Type I, also called sialidosis, is usually recognizable at birth or soon after. Babies with sialidosis are usually born with facial deformities and red spots in their eyes. The infants may have other physical deformities and suffer from seizures, vision problems, and mental retardation. This form of the disease also causes inflammation of the spleen and liver, and most infants born with the disease die before their first birthday.
Type II is another severe form of the disease and causes many of the same symptoms as sialidosis. Children born with this type do not grow normally, which often results in short-trunk dwarfism. They also suffer from respiratory problems during their first years of life, including infections, pneumonia, and bronchitis, and typically die from respiratory complications or congestive heart failure before the age of seven.
The third type is a much milder form of the disease and often goes undetected until a child is close to school age. Many children with type III mucolipidosis do not suffer from mental disabilities, and the ones who do typically only have mild learning disabilities. Children with this type of the disease often live until their 40s or 50s, though they may suffer from physical deformities, including vision problems and short height.
Mucolipidosis type IV patients display many of the same symptoms as children with type III. While children with type IV may not suffer from severe mental retardation, they often develop speech problems and have trouble walking. This type of the disease is usually diagnosed before the child's toddler years and is more common in children born to Jewish parents.