Hearing loss can attribute to decrease in health-related quality of life, increase in social isolation and decline in social engagement, which are all risk factors for increased risk of developing depression symptoms. Spoken language ability
Post-lingual deafness is hearing loss that is sustained after the acquisition of language, which can occur due to disease, trauma, or as a side-effect of a medicine. Typically, hearing loss is gradual and often detected by family and friends of affected individuals long before the patients themselves will acknowledge the disability. Post-lingual deafness is far more common than pre-lingual deafness. Those who lose their hearing later in life, such as in late adolescence or adulthood, face their own challenges, living with the adaptations that allow them to live independently. Prelingual deafness is profound hearing loss that is sustained before the acquisition of language, which can occur due to a congenital condition or through hearing loss before birth or in early infancy. Prelingual deafness impairs an individuals ability to acquire a spoken language in children, but deaf children can acquire spoken language through support from cochlear implants (sometimes combined with hearing aids). Non-signing (hearing) parents of deaf babies (90–95% of cases) usually go with oral approach without the support of sign language, as these families lack previous experience with sign language and cannot competently provide it to their children without learning it themselves.
Iduronidase (EC 3.2.1.76, L-iduronidase, alpha-L-iduronidase, laronidase), sold as Aldurazyme, is an enzyme with the systematic name glycosaminoglycan alpha-L-iduronohydrolase. This enzyme catalyses the hydrolysis of unsulfated alpha-L-iduronosidic linkages in dermatan sulfate.It is a glycoprotein enzyme found in the lysosomes of cells. It is involved in the degeneration of glycosaminoglycans such as dermatan sulfate and heparan sulfate. The enzyme acts by hydrolyzing the terminal alpha-L-iduronic acid residues of these molecules, degrading them. The protein is reported as having a mass of approximately 83 kilodaltons. Pathology
A deficiency in the IDUA protein is associated with mucopolysaccharidoses (MPS). MPS, a type of lysosomal storage disease, is typed I through VII. Type I is known as Hurler syndrome and type I,S is known as Scheie syndrome, which has a milder prognosis compared to Hurlers. In this syndrome, glycosaminoglycans accumulate in the lysosomes and cause substantial disease in many different tissues of the body. IDUA mutations result in the MPS 1 phenotype, which is inherited in an autosomal recessive fashion. The defective alpha-L-iduronidase results in an accumulation of heparan and dermatan sulfate within phagocytes, endothelium, smooth muscle cells, neurons, and fibroblasts. Under electron microscopy these structures present as laminated structures called Zebra bodies. Prenatal diagnosis of this enzyme deficiency is possible. Aldurazyme
General
Aldurazyme is the name of the commercialized variant of the enzyme iduronidase, which hydrolyzes the alpha-L-iduronic acid residues of dermatan sulfate and heparin sulfate. Produced in Chinese hamster ovaries by recombinant DNA technology, Aldurazyme is the manufactured by BioMarin Pharmaceutical Inc. and distributed by Genzyme Corporation (a subsidiary of Sanofi).