user: What are the symptoms of Pantothenate kinase-associated neurodegeneration ?

assistant: What are the signs and symptoms of Pantothenate kinase-associated neurodegeneration? There are two forms of PKAN, classical and atypical. Symptoms of classic PKAN develop during early childhood, usually before age 10. The first symptom is often difficutly with movement and walking. Children are often first considered clumsy as their legs can be rigid, dystonic (an abnormality of muscle tone) and have involuntary muscle spasms (spasticity); these symptoms worsen over time.  People can plateau for long periods of time and then undergo intervals of rapid deterioration, often lasting one to two months. Children usually lose the ability to walk by 10-15 years after the beginning of symptoms.  Many individuals also experience limited speech and may have enough trouble with chewing and swallowing that a feeding tube becomes necessary. Two-thirds of children with classical PKAN develop peripheral (side) vision loss and night blindness due to retinal degeneration. Cognitive functioning varies from person to person and can range from high average to below average. Premature death does occur; however, live span is variable. With improvements in medical care, a greater number of affected individuals are living into adulthood. All individuals with PKAN have an abnormal buildup of iron in certain areas of the brain. A particular change, called the eye-of-the-tiger sign, which indicates an accumulation of iron, is typically seen on magnetic resonance imaging (MRI) scans of the brain in people with this disorder. Features of the atypical form usually progress more slowly and appear within the first three decades of life. Signs and symptoms vary, but the progression in the atypical form is usually slower. Symptoms are usually marked by speech difficulty such repetition of words or phrases (palilalia), rapid speech (tachylalia), and poor articulation/slurring (dysarthria). Psychiatric symptoms such as behavioral problems, personality changes, and depression are more commonly observed. While movement problems are a common feature, it usually develops later. Loss of independent walking often occurs 15-40 years after the initial development of symptoms. Retinal degeneration is rare in the atypical form. The Human Phenotype Ontology provides the following list of signs and symptoms for Pantothenate kinase-associated neurodegeneration. 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 retinal pigmentation 90% Gait disturbance 90% Neurological speech impairment 90% Abnormality of the cranial nerves 50% Abnormality of the foot 50% Chorea 50% Constipation 50% Feeding difficulties in infancy 50% Hyperreflexia 50% Hypertonia 50% Recurrent respiratory infections 50% Tremor 50% Weight loss 50% Abnormal joint morphology 7.5% Developmental regression 7.5% Seizures 7.5% Visual impairment 7.5% Abnormal pyramidal signs - Acanthocytosis - Akinesia - Ataxia - Autosomal recessive inheritance - Behavioral abnormality - Blepharospasm - Bradykinesia - Cerebral degeneration - Choreoathetosis - Decreased muscle mass - Dementia - Depression - Dysarthria - Dysphagia - Dysphonia - Eye of the tiger anomaly of globus pallidus - Eyelid apraxia - Facial grimacing - Global brain atrophy - Hyperactivity - Hyperpigmentation of the skin - Motor tics - Myopathy - Neurodegeneration - Obsessive-compulsive trait - Optic atrophy - Orofacial dyskinesia - Parkinsonism - Pigmentary retinopathy - Rapidly progressive - Retinal degeneration - Rigidity - Spasticity - Urinary incontinence - 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.