- Strabismus (HP:0000486): A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error. Evidence: IEA. (OMIM:208900)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Short stature (HP:0004322): A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms). Evidence: IEA. (OMIM:208900)
- Recurrent lower respiratory tract infections (HP:0002783): An increased susceptibility to lower respiratory tract infections as manifested by a history of recurrent lower respiratory tract infections. Evidence: PCS. Frequency: 2/2. (PMID:22563157)
- Dystonia (HP:0001332): An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk. Evidence: TAS. (OMIM:208900)
- Seizure (HP:0001250): A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: PCS. Frequency: 104/104. (PMID:17628218)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Childhood onset (HP:0011463): Onset of disease at the age of between 1 and 5 years. Evidence: PCS. Frequency: 2/2. (PMID:22563157)
- Cafe-au-lait spot (HP:0000957): Cafe-au-lait spots are hyperpigmented lesions that can vary in color from light brown to dark brown with smooth borders and having a size of 1.5 cm or more in adults and 0.5 cm or more in children. Evidence: IEA. (OMIM:208900)
- Decreased total lymphocyte count (HP:0001888): A reduced number of lymphocytes in the blood. Evidence: TAS. (OMIM:208900)
- Decreased circulating IgG concentration (HP:0004315): An abnormally decreased level of immunoglobulin G (IgG) in blood. Evidence: IEA. (OMIM:208900)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Female hypogonadism (HP:0000134): Decreased functionality of the female gonads, i.e., of the ovary. Evidence: IEA. (OMIM:208900)
- Choreoathetosis (HP:0001266): Involuntary movements characterized by both athetosis (inability to sustain muscles in a fixed position) and chorea (widespread jerky arrhythmic movements). Evidence: PCS. Frequency: 81/93. (PMID:17628218)
- Dysarthria (HP:0001260): Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed. Evidence: PCS. Frequency: 104/104. (PMID:17628218)
- Bronchiectasis (HP:0002110): Persistent abnormal dilatation of the bronchi owing to localized and irreversible destruction and widening of the large airways. Evidence: IEA. (OMIM:208900)
- Dysdiadochokinesis (HP:0002075): A type of ataxia characterized by the impairment of the ability to perform rapidly alternating movements, such as pronating and supinating his or her hand on the dorsum of the other hand as rapidly as possible. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Progressive cerebellar ataxia (HP:0002073). Evidence: PCS. Frequency: 2/2. (PMID:22563157)
- Non-Hodgkin lymphoma (HP:0012539): A type of lymphoma characterized microscopically by the absence of multinucleated Reed-Sternberg cells. Evidence: TAS. (OMIM:208900)
- Hodgkin lymphoma (HP:0012189): A type of lymphoma characterized microscopically by multinucleated Reed-Sternberg cells. Evidence: TAS. (OMIM:208900)
- Conjunctival telangiectasia (HP:0000524): The presence of small (ca. 0.5-1.0 mm) dilated blood vessels near the surface of the mucous membranes of the conjunctiva. Evidence: PCS. Frequency: 2/2. Onset: Childhood onset (HP:0011463). (PMID:22563157)
- Autosomal recessive inheritance (HP:0000007): A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Evidence: PCS. (PMID:7792600)
- Sinusitis (HP:0000246): Inflammation of the paranasal sinuses owing to a viral, bacterial, or fungal infection, allergy, or an autoimmune reaction. Evidence: IEA. (OMIM:208900)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: TAS. (OMIM:208900)
- Lymphoma (HP:0002665): A cancer originating in lymphocytes and presenting as a solid tumor of lymhpoid cells. Evidence: IEA. (OMIM:208900)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: TAS. (OMIM:208900)
- Chronic diarrhea (HP:0002028): The presence of chronic diarrhea, which is usually taken to mean diarrhea that has persisted for over 4 weeks. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Abnormal hair morphology (HP:0001595): An abnormality of the hair. Evidence: IEA. (OMIM:208900)
- Defective B cell differentiation (HP:0005357): Reduced functionality of the process in which a precursor cell type acquires the specialized features of a B cell. A B cell is a lymphocyte of B lineage with the phenotype CD19-positive and capable of B cell mediated immunity. Evidence: IEA. (OMIM:208900)
- Slurred speech (HP:0001350): Abnormal coordination of muscles involved in speech. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Intention tremor (HP:0002080): A type of kinetic tremor that occurs during target directed movement is called intention tremor. That is, an oscillatory cerebellar ataxia that tends to be absent when the limbs are inactive and during the first part of voluntary movement but worsening as the movement continues and greater precision is required (e.g., in touching a target such as the patient's nose or a physician's finger). Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Decreased total CD4+ T cell proportion (HP:0032218): Abnormal decrease of helper CD3+CD4+ T cells, measured as percentage of total CD3+ T cells in the blood, compared to a reference range for a given sex and age-group. These are usually measured within the TCR alpha/beta positive population. Evidence: TAS. (OMIM:208900)
- Diabetes mellitus (HP:0000819): A group of abnormalities characterized by hyperglycemia and glucose intolerance. Evidence: TAS. (OMIM:208900)
- Leukemia (HP:0001909): A cancer of the blood and bone marrow characterized by an abnormal proliferation of leukocytes. Evidence: IEA. (OMIM:208900)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: PCS. Frequency: 39/104. (PMID:17628218)
- Hypoplasia of the thymus (HP:0000778): Underdevelopment of the thymus. Evidence: IEA. (OMIM:208900)
- Elevated circulating alpha-fetoprotein concentration (HP:0006254): The concentration of alpha-fetoprotein in the blood circulation is above the upper limit of normal. Evidence: PCS. Frequency: 2/2. (PMID:22563157)
- Recurrent bronchitis (HP:0002837): An increased susceptibility to bronchitis as manifested by a history of recurrent bronchitis. Evidence: IEA. (OMIM:208900)
- Decreased total T cell count (HP:0005403): Abnormal decrease in the absolute number of T cells, commonly characterized as CD3+ lymphocytes, per microliter of blood, compared to a reference range for a given sex and age-group. These may include both TCR alpha/beta and gamma/delta T cells. Evidence: TAS. (OMIM:208900)
- Delayed speech and language development (HP:0000750): A degree of language development that is significantly below the norm for a child of a specified age. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Abnormal total B cell count (HP:0010975): The absolute number of B cells in the blood, per microlitre is outside the limits of normal of the reference range for the appropriate sex and age-group. Evidence: PCS. Frequency: 0/2. (PMID:22563157)
- Delayed puberty (HP:0000823): Passing the age when puberty normally occurs with no physical or hormonal signs of the onset of puberty. Evidence: IEA. (OMIM:208900)
- Decreased circulating IgG2 concentration (HP:0008348): A reduction in immunoglobulin levels of the IgG2 subclass in the blood circulation. Evidence: IEA. (OMIM:208900)
- Acute lymphoblastic leukemia (HP:0006721): A form of acute leukemia characterized by excess lympoblasts. Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Diminished deep tendon reflex (HP:0001315): A reduction (hyporeflexia) or complete absence (areflexia) of the involuntary muscle contraction normally elicited by a reflex stimulus, such as tapping a deep tendon. Evidence: IEA. (OMIM:208900)
- Decreased circulating IgA concentration (HP:0002720): Decreased levels of immunoglobulin A (IgA). Evidence: PCS. Frequency: 1/2. (PMID:22563157)
- Glucose intolerance (HP:0001952): Glucose intolerance (GI) can be defined as dysglycemia that comprises both prediabetes and diabetes. It includes the conditions of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) and diabetes mellitus (DM). Evidence: IEA. (OMIM:208900)
- Abnormal spermatogenesis (HP:0008669): Incomplete maturation or aberrant formation of the male gametes. Evidence: IEA. (OMIM:208900)
These phenotypes are associated with the disease ataxia telangiectasia (OMIM:208900).