- Intellectual disability (HP:0001249): The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- 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: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Flexion contracture (HP:0001371): A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Distal muscle weakness (HP:0002460): Reduced strength of the musculature of the distal extremities. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Elbow flexion contracture (HP:0002987): An elbow contracture that limits the ability of the elbow joint to be extended (straightened), meaning that the elbow is fixed in an flexed (bent) position. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Knee flexion contracture (HP:0006380): A type of knee joint contracture in which the knee is in a fixed bent (flexed) configuration such that it cannot be straightened actively or passively. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Ankle flexion contracture (HP:0006466). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Upper limb hyperreflexia (HP:0007350): Increased intensity of the a reflex in the arm. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Bilateral wrist flexion contracture (HP:0012453): A chronic loss of wrist joint motion on the right and left sides. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:209951)
- Wide mouth (HP:0000154): Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:209951)
- Macroglossia (HP:0000158): Increased length and width of the tongue. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:209951)
- Spasticity (HP:0001257): A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:209951)
- Absent speech (HP:0001344): Complete lack of development of speech and language abilities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:209951)
- Hypoplasia of the corpus callosum (HP:0002079): Underdevelopment of the corpus callosum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:209951)
- Babinski sign (HP:0003487): Upturning of the big toe (and sometimes fanning of the other toes) in response to stimulation of the sole of the foot. If the Babinski sign is present it can indicate damage to the corticospinal tract. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:209951)
- High palate (HP:0000218): Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Short philtrum (HP:0000322): Distance between nasal base and midline upper lip vermilion border more than 2 SD below the mean. Alternatively, an apparently decreased distance between nasal base and midline upper lip vermilion border. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Abnormal pinna morphology (HP:0000377): An abnormality of the pinna, which is also referred to as the auricle or external ear. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Thick eyebrow (HP:0000574): Increased density/number and/or increased diameter of eyebrow hairs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Synophrys (HP:0000664): Meeting of the medial eyebrows in the midline. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Horizontal nystagmus (HP:0000666): Nystagmus consisting of horizontal to-and-fro eye movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- 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: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Rotary nystagmus (HP:0001583): A form of nystagmus in which the eyeball makes rotary motions around the axis. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Dysphagia (HP:0002015): Difficulty in swallowing. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Impaired vibration sensation in the lower limbs (HP:0002166): A decrease in the ability to perceive vibration in the legs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Hand tremor (HP:0002378): An unintentional, oscillating to-and-fro muscle movement affecting the hand. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Hip contracture (HP:0003273): Lack of full passive range of motion (restrictions in flexion, extension, or other movements) of the hip joint resulting from structural changes of non-bony tissues, such as muscles, tendons, ligaments, joint capsules and/or skin. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Spinal rigidity (HP:0003306): Reduced ability to move the vertebral column with a resulting limitation of neck and trunk flexion. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Flexion contracture of toe (HP:0005830): One or more bent (flexed) toe joints that cannot be straightened actively or passively. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Neck joint contracture (HP:0005997). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Ankle clonus (HP:0011448): Clonus is an involuntary tendon reflex that causes repeated flexion and extension of the foot. Ankle clonus is tested by rapidly flexing the foot upward. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
- Abnormal lumbar spine morphology (HP:0100712): Any structural abnormality of the lumbar vertebral column. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:209951)
These phenotypes are associated with the disease Autosomal spastic paraplegia type 18 (ORPHA:209951).