Question: What is (are) Refsum disease, infantile form ?
Answer: Infantile Refsum disease is the mildest of a group of disorders known as peroxisome biogenesis disorders, Zellweger syndrome spectrum (PBD-ZSS). PBD-ZSS is a group of inherited genetic disorders that damage the white matter of the brain and affect motor movements. Peroxisome biogenesis disorders, in turn, are part of a larger group of disorders called leukodystrophies. IRD can cause low muscle tone (hypotonia), retinitis pigmentosa (a visual impairment that can lead to blindness), developmental delay, sensorineural hearing loss, and liver dysfunction. IRD usually presents at birth or in infancy. Most individuals with IRD can achieve motor milestones, though they may be delayed, and most individuals can communicate with a few words or signs. Leukodystrophy with loss of acquired skills can occur at any age and may stabilize or progress. Peroxisome biogenesis disorders are caused by mutations in one of the PEX genes and are inherited in an autosomal recessive manner. Life expectancy, medical complications, and the degree of neurological impairment can vary. Survival into adulthood is possible. Adult Refsum disease and infantile refsum disease are separate disorders caused by different genetic defects.
Source: GARD

Question: What are the symptoms of Refsum disease, infantile form ?
Answer: What are the signs and symptoms of Refsum disease, infantile form? The Human Phenotype Ontology provides the following list of signs and symptoms for Refsum disease, infantile form. 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) Abnormality of metabolism/homeostasis 90% Abnormality of retinal pigmentation 90% Cognitive impairment 90% Hepatomegaly 90% Nyctalopia 90% Short stature 90% Skeletal muscle atrophy 90% Visual impairment 90% Behavioral abnormality 50% Hypertonia 50% Incoordination 50% Muscular hypotonia 50% Nystagmus 50% Sensorineural hearing impairment 50% Abnormality of epiphysis morphology 7.5% Arrhythmia 7.5% Cataract 7.5% Facial palsy 7.5% Hypertrophic cardiomyopathy 7.5% Ichthyosis 7.5% Optic atrophy 7.5% Seizures 7.5% Abnormal bleeding - Abnormal electroretinogram - Abnormal facial shape - Autosomal recessive inheritance - Congenital onset - Depressed nasal ridge - Failure to thrive - Flat face - Hypocholesterolemia - Hyporeflexia - Intellectual disability - Malar flattening - Osteoporosis - Polyneuropathy - Rod-cone dystrophy - Single transverse palmar crease - Steatorrhea - Very long chain fatty acid accumulation - 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