Medical Definition of Morquio syndrome

Morquio syndrome: genetic error of carbohydrate metabolism causing mucopolysaccharide accumulation and severe bone defect. Birth defects including severe malformation of the spine and chest, short neck, loose expanded joint, irregular end of long bone. This disease is autosomal recessive inheritance

Severe growth retardation (adult height is 82 - 115 cm), the skull is very thick, dense, corneal opacity (eye turbidity), there are deafness. The liver is slightly enlarged. There are many abnormalities in the spine (sudden onset, dental hypoplasia, cervical subluxation and cervical spondylosis myelopathy). The chest is a pigeon-type (decayed tooth). Relaxation of knot and knee joint (varusal knee) and hip joint deformity (dysplasia). Intelligence is normal. (In other words there is no tendency to mental retardation.) There are several abnormal laboratory findings (fibroblasts and amniotic fluid, galactosamine-6-sulfatase deficiency in keratin sulfate in age-associated urine) of leukocytes and fibroblasts As with heterofection, growth decreases. An error in carbohydrate metabolism is the lack of galactosamine-6-sulfatase. So far, enzyme replacement therapy is not effective. Amniocentesis permits prenatal diagnosis. As mentioned above, the inheritance is autosomal recessive, meaning that normal parents each possess the Morquio gene and that their boys and girls each receive two parents of the Morquio gene and the risk of having this disease Means there is. 4 (25%) Morquio gene is located on chromosome 16 (chromosome band 16q24.3)

This situation was first described by Luis Morquio of Montevideo in Uruguay in 1929 and by JF Brailsford in Birmingham, England. They all recognize corneal opacity, aortic valve disease and keratin sulfate excretion. Morquio observed the illness of four brothers and sisters of the Swedish family, further aggravated international confounding factors and reported his observations in French (Non-Patent Document 2). This disease should be called Morquio-Brailsford (or vice versa) syndrome, but it is rarely done, but the Morquio syndrome is sometimes referred to as the biochemical name - mucopolysaccharidosis type IV (IV). MPS IV)

Morquio syndrome (called mucopolysaccharidosis IV, MPS IV, Morquio-Brailsford syndrome or Morquio) is a rare metabolic disorder in which the body can not handle certain types of mucopolysaccharides (long chain sugar molecules). The body functions as a lubricant and shock absorber. This congenital deficiency is an autosomal recessive inheritance and is therefore a commonly inherited lysosomal storage disease. : 544 In the United States, the prevalence of Morquio is estimated to be between 20 and 100,000 births.

This syndrome has two forms, Morquio A and Morquio B syndrome, or A and B called MPA IVA and MPS IVB. These two forms are characterized by the gene products involved; A is responsible for the dysfunction of the GALNS gene product (galactosamine-6 ​​sulfatase) and B is responsible for the dysfunction of the GLB1 gene product (β-galactosidase). The human GLB1 gene is located in chromosome band 3p22.3 and encodes β-galactosidase-1, a lysosomal hydrolase that cleaves terminal β-galactose from ganglioside substrate and other glycoconjugates. A loss-of-function allele typically results in a series of GM1-ganglioside disorders. However, certain alleles, including combinations with the most common subspecies of W273L, may cause Morquio B syndrome

B type Morquio syndrome was originally identified as a milder type A disease, but it was subsequently shown to be a result of a genetic defect different from the gene that caused the type A phenotype. Type B Morquio is characterized by systemic skeletal dysplasia, leading to short stature, sternum (sternal bulge), platysma, scoliosis and dedoptic hypoplasia. Morquio type B disease is not affected by the central nervous system and has normal intelligence. As mentioned above, this disease is caused by a mutation in the β-galactosidase gene that is different from the mutation causing GM1 ganglioside accumulation disease.