Question: What are the symptoms of Hoyeraal Hreidarsson syndrome ?
Answer: What are the signs and symptoms of Hoyeraal Hreidarsson syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for Hoyeraal Hreidarsson syndrome. 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 immune system physiology 90% Aplasia/Hypoplasia of the cerebellum 90% Cognitive impairment 90% Intrauterine growth retardation 90% Microcephaly 90% Short stature 90% Subcutaneous hemorrhage 90% Thrombocytopenia 90% Abnormal hair quantity 50% Abnormality of coagulation 50% Abnormality of the nail 50% Abnormality of the oral cavity 50% Anemia 50% Cerebral cortical atrophy 50% Generalized hyperpigmentation 50% Hypertonia 50% Hypopigmentation of hair 50% Ventriculomegaly 50% Abnormality of leukocytes 7.5% Bone marrow hypocellularity 7.5% Cerebral calcification 7.5% Incoordination 7.5% Neoplasm 7.5% 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