Specialty endocrinology ICD-9-CM 277.5 DiseasesDB 30807 30806 | ICD-10 E76.2 OMIM 253000 253010 MedlinePlus 001206 | |
Morquio syndrome (referred to as mucopolysaccharidosis IV, MPS IV, Morquio-Brailsford syndrome, or Morquio) is an autosomal recessive mucopolysaccharide storage disease (see also lysosomal storage disorder), usually inherited. It is a rare type of birth defect with serious consequences. In the US, the incidence rate for Morquio is estimated at between 1 in 200,000 and 1 in 300,000 live births.
Contents
When the body cannot process certain types of mucopolysaccharides, they build up or are eliminated, causing various symptoms. These involve accumulation of keratan sulfate.
Classification
This syndrome has two forms, A and B, referred to as Morquio A and Morquio B syndrome or MPA IVA and MPS IVB. The two forms are distinguished by the gene product involved; A involves a malfunction in the GALNS gene product (galactosamine-6 sulfatase), while B involves a malfunction of the GLB1 gene product (beta-galactosidase).
History
The condition was first described, simultaneously and independently, in 1929, by Luis Morquio (1867–1935), a prominent Uruguayan physician who discovered it in Montevideo, and James Frederick Brailsford (1888–1961), an English radiographer in Birmingham, England. They both recognized the occurrence of corneal clouding, aortic valve disease, and urinary excretion of keratan sulfate. Morquio observed the disorder in four siblings in a family of Swedish extraction and reported his observations in French.
Signs
The following signs are associated with Morquio's syndrome:
Symptoms
Patients with Morquio syndrome appear healthy at birth. They often present with spinal deformity, and there is growth retardation and possibly genu valgum in the second or third year of life. A patient with Morquio's syndrome is likely to die at an early age. Symptoms of the disease may include:
Regarding the life span of people with Morquio, some can die as early as 2 or 3 years old, and some can live up to 60 or 70 years old. The oldest living person with Morquio syndrome type IV A is Kenneth D. Martin, who is 80 years old and was born in Osage City, Kansas, USA.
Treatment
The treatment for Morquio syndrome consists of prenatal identification and of enzyme replacement therapy. On 12 February 2014, the US Food and Drug Administration approved the drug elosulfase alfa (Vimizim) for treating the disease.