<unk>  may present with a wide variety of phenotypes. It has traditionally been categorized as either "mild" or "severe" depending on the presence of central nervous system symptoms, but this is an oversimplification. Patients with "attenuated" or "mild" forms of the disease may still suffer from significant health issues. For severely affected patients, the clinical course is relatively predictable; patients will normally die at an early age. For those with milder forms of the disease, a wider variety of outcomes exist. Many live into their 20s and 30s, but some may have near-normal life expectancies. Cardiac and respiratory abnormalities are the usual cause of death for patients with milder forms of the disease. The symptoms of<unk>  (MPS II) are generally not apparent at birth. Often, the first symptoms may include abdominal hernias, ear infections, runny noses, and colds. As the buildup of GAGs continues throughout the cells of the body, signs of MPS II become more visible. Physical appearances of many children with the syndrome include a distinctive coarseness in their facial features, including a prominent forehead, a nose with a flattened bridge, and an enlarged tongue. They may also have a large head, as well as an enlarged abdomen. For severe cases of MPS II, a diagnosis is often made between the ages of 18 and 36 months. In milder cases, patients present similarly to children with Hurler–Scheie syndrome, and a diagnosis is usually made between the ages of 4 and 8 years. The continued storage of GAGs leads to abnormalities in multiple organ systems. After 18 months, children with severe MPS II may suffer from developmental decline and progressive loss of skills. The thickening of the heart valves and walls of the heart can result in progressive decline in cardiac function. The walls of the airway may become thickened, as well, leading to obstructive airway disease. As the liver and spleen grow larger with time, the abdomen may become distended, making hernias more noticeable. All major joints may be affected by MPS II, leading to joint stiffness and limited motion. Progressive involvement of the finger and thumb joints results in decreased ability to pick up small objects. The effects on other joints, such as hips and knees, can make walking normally increasingly difficult. If carpal tunnel syndrome develops, a further decrease in hand function can occur. The bones themselves may be affected, resulting in short stature. In addition, pebbly, ivory-colored skin lesions may be found on the upper arms, legs, and upper back of some people with it. These skin lesions are considered pathognomic for the disease. Finally, the storage of GAGs in the brain can lead to delayed development with subsequent intellectual disability and progressive loss of function. The age at onset of symptoms and the presence or absence of behavioral disturbances are predictive factors of ultimate disease severity in very young patients. Behavioral disturbances can often mimic combinations of symptoms of attention deficit hyperactivity disorder, autism, obsessive compulsive disorder, and/or sensory processing disorder, although the existence and level of symptoms differ in each affected child. They often also include a lack of an appropriate sense of danger, and aggression. The behavioral symptoms of MPS II generally precede neurodegeneration and often increase in severity until the mental handicaps become more pronounced. By the time of death, most children with severe MPS II have severe mental disabilities and are completely dependent on their caretakers.
Hunter syndrome
Mucopolysaccharidosis type I
Laron syndrome
Mucopolysaccharidosis
Sabinas brittle hair syndrome
Malouf syndrome
Hurler syndrome
TORCH syndrome