Pseudo-Hurler polydystrophy, also referred to as

mucolipidosis Mucolipidosis is a group of inherited metabolic disorders that affect the body's ability to carry out the normal turnover of various materials within cells. When originally named, the mucolipidoses derived their name from the similarity in p ...

III (ML III), is a lysosomal storage disease closely related to I-cell disease (ML II). This disorder is called Pseudo-Hurler because it resembles a mild form of Hurler syndrome, one of the mucopolysaccharide (MPS) diseases.

Signs and symptoms

Symptoms of ML III are often not noticed until the child is 3–5 years of age. Patients with ML III are generally of normal

intelligence Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as t ...

(trait) or have only mild

mental retardation Intellectual disability (ID), also known as general learning disability (in the United Kingdom), and formerly mental retardation (in the United States), Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010).Archive is a generalized neurodevelopmental ...

(intelligence is challenged) instead of using the mental retardation classification. These patients usually have skeletal abnormalities, coarse facial features, short height, corneal clouding,

carpal tunnel syndrome Carpal tunnel syndrome (CTS) is a nerve compression syndrome associated with the collected signs and symptoms of Pathophysiology of nerve entrapment#Compression, compression of the median nerve at the carpal tunnel in the wrist. Carpal tunn ...

aortic valve The aortic valve is a valve in the heart of humans and most other animals, located between the left ventricle and the aorta. It is one of the four valves of the heart and one of the two semilunar valves, the other being the pulmonary valve. ...

disease and mild enlargement of organs. Some children with severe forms of this disease do not live beyond childhood. However, there is a great variability among patients – there are diagnosed individuals with ML III living in their sixties.

Pathophysiology

As in Mucolipidosis II (I-cell disease), Mucolipidosis III results from genetic defects in GlcNAc phosphotransferase ( N-acetylglucosamine-1-phosphotransferase). However, ML III produces less severe symptoms and progresses more slowly, probably because the defect in GlcNAc phosphotranspherase lies in its protein recognition domain.Murray, R, Granner, D, and Rodwell, V. (2006). Harper's Illustrated Biochemistry. 27th ed. New York: Lange Medical Books/McGraw-Hill. Therefore, the catalytic domain retains some of its activity, resulting in a smaller accumulation of carbohydrates, lipids, and proteins in the

inclusion bodies Inclusion bodies are aggregates of specific types of protein found in neurons, and a number of tissue (biology), tissue cells including red blood cells, bacteria, viruses, and plants. Inclusion bodies of aggregations of multiple proteins are also ...

Diagnosis

Treatment

There is no cure for Pseudo-Hurler Polydystrophy/Mucolipidosis IIIA. Treatment is limited to controlling or reducing symptoms associated with this disorder. Physio-therapy, particularly

hydrotherapy Hydrotherapy, formerly called hydropathy and also called water cure, is a branch of alternative medicine (particularly naturopathy), occupational therapy, and Physical therapy, physiotherapy, that involves the use of water for pain relief and ...

has proven effective at relieving muscle stiffness and increasing mobility. The use of crutches, a wheelchair or scooters are treatment options as the metabolic bone disease progresses. The insertion of rods in the spine to stabilize the vulnerable areas can treat

scoliosis Scoliosis (: scolioses) is a condition in which a person's Vertebral column, spine has an irregular curve in the coronal plane. The curve is usually S- or C-shaped over three dimensions. In some, the degree of curve is stable, while in others ...

. Heart valve replacement surgery may be necessary as this disorder progresses. Enzyme replacement therapy has been suggested as a potential treatment.

References

External links