Question: What is (are) Mucopolysaccharidosis type IIID ?
Answer: Mucopolysaccharidosis type IIID (MPS IIID) is an genetic disorder that makes the body unable to break down large sugar molecules called glycosaminoglycans (GAGs, formerly called mucopolysaccharides). Specifically, people with this condition are unable to break down a GAG called heparan sulfate. Affected individuals can have severe neurological symptoms, including progressive dementia, aggressive behavior, hyperactivity, seizures, deafness, loss of vision, and an inability to sleep for more than a few hours at a time. MPS IIID is caused by the missing or deficient enzyme N-acetylglucosamine 6-sulfatase. MPS IIID is inherited in an autosomal recessive manner. There is no specific treatment for this condition. Most people with MPS IIID live into their teenage years, and some live longer.
Source: GARD

Question: What are the symptoms of Mucopolysaccharidosis type IIID ?
Answer: What are the signs and symptoms of Mucopolysaccharidosis type IIID? The Human Phenotype Ontology provides the following list of signs and symptoms for Mucopolysaccharidosis type IIID. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Absent speech - Anteverted nares - Asymmetric septal hypertrophy - Autosomal recessive inheritance - Cellular metachromasia - Coarse facial features - Coarse hair - Depressed nasal bridge - Diarrhea - Drooling - Dysarthria - Dysostosis multiplex - Dysphagia - Flexion contracture - Frontal bossing - Growth abnormality - Hearing impairment - Heparan sulfate excretion in urine - Hepatomegaly - Hirsutism - Hyperactivity - Intellectual disability - Joint stiffness - Low-set ears - Ovoid thoracolumbar vertebrae - Progressive - Prominent forehead - Recurrent upper respiratory tract infections - Seizures - Short neck - Sleep disturbance - Splenomegaly - Synophrys - Thick eyebrow - Thick lower lip vermilion - Thickened ribs - Wide mouth - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD