- Progressive muscle weakness (HP:0003323). Evidence: PCS. (PMID:24911150)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: PCS. (PMID:24911150)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: PCS. Frequency: 3/4. (PMID:24911150)
- Progressive (HP:0003676): Applies to a disease manifestation that increases in scope or severity over the course of time, i.e., that worsens with age. Evidence: PCS. (PMID:24911150)
- Cutaneous photosensitivity (HP:0000992): An increased sensitivity of the skin to light. Photosensitivity may result in a rash upon exposure to the sun (which is known as photodermatosis). Photosensitivity can be diagnosed by phototests in which light is shone on small areas of skin. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- Pes cavus (HP:0001761): An increase in height of the medial longitudinal arch of the foot that does not flatten on weight bearing (i.e., a distinctly hollow form of the sole of the foot when it is bearing weight). Evidence: PCS. (PMID:24911150)
- 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: PCS. Frequency: 4/4. (PMID:24911150)
- Cerebellar atrophy (HP:0001272): Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event. Evidence: PCS. Frequency: 1/1. (PMID:24911150)
- 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. (PMID:24911150)
- Global developmental delay (HP:0001263): A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- 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: 4/4. (PMID:24911150)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- Cutaneous telangiectasia (HP:0034697): Dilated blood vessels on the skin. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- Neurodegeneration (HP:0002180): Progressive loss of neural cells and tissue. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- Joint contracture (HP:0034392): A limitation in the passive range of motion of a joint resulting from loss of elasticity in the periarticular tissues owing to structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules or skin. A contracture prevents movement of the associated body part. Evidence: PCS. Frequency: 1/4. (PMID:24911150)
- Sensorineural hearing impairment (HP:0000407): A type of hearing impairment in one or both ears related to an abnormal functionality of the cochlear nerve. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- Absent pubertal growth spurt (HP:0031087): The abrupt and transient increase in the annual growth rate normally observed in adolescent individuals does not occur. Evidence: PCS. Frequency: 2/4. (PMID:24911150)
- Photophobia (HP:0000613): Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light. Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- 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:24911150)
- 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: 3/4. (PMID:24911150)
- Unsteady gait (HP:0002317). Evidence: PCS. Frequency: 4/4. (PMID:24911150)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: PCS. (PMID:24911150)
- Congenital diaphragmatic hernia (HP:0000776): The presence of a hernia of the diaphragm present at birth. Evidence: PCS. Frequency: 1/4. (PMID:24911150)
- Progeroid facial appearance (HP:0005328): A degree of wrinkling of the facial skin that is more than expected for the age of the individual, leading to a prematurely aged appearance. Evidence: PCS. Frequency: 1/2. (PMID:24911150)
These phenotypes are associated with the disease ataxia-telangiectasia-like disorder 2 (OMIM:615919).