- Abnormality of visual evoked potentials (HP:0000649): An anomaly of visually evoked potentials (VEP), which are electrical potentials, initiated by brief visual stimuli, which are recorded from the scalp overlying the visual cortex. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Irritability (HP:0000737): An emotional state characterized by negative feelings of heightened frustration, annoyance, or feeling upset, often triggered by internal factors (e.g., fatigue, hunger, unfulfilled desires) or external factors (e.g., social or environmental challenges). Irritability may be unpredictable, and is accompanied by a lowered threshold for emotional reactivity and observable features (speech, facial expressions, or psychomotor activity). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- 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: Very frequent (HP:0040281). (ORPHA:206436)
- Mental deterioration (HP:0001268): Loss of previously present mental abilities, generally in adults. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Unexplained fevers (HP:0001955): Episodes of fever for which no infectious cause can be identified. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Progressive neurologic deterioration (HP:0002344). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Increased CSF protein concentration (HP:0002922): Increased concentration of protein in the cerebrospinal fluid. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Functional motor deficit (HP:0004302). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Sensorimotor neuropathy (HP:0007141). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Abnormal circulating enzyme concentration or activity (HP:0012379): Concentration or activity of an enzyme is above or below the limits of normal in the blood circulation. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Inappropriate crying (HP:0030215): Uncontrolled episodes of crying occur without any apparent motivating stimuli. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Hyperpyrexia (HP:0033031): An extreme elevation of core body temperature above normal defined as a rectal temperature of 41.1 degrees Celsius (106 degrees Fahrenheit). Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Reduced tissue galactocerebrosidase activity (HP:0034322): Concentration or activity of galactocerebrosidase (EC 3.2.1.46) below the lower limit of normal. This enzyme can be measured in multiple tissues including leukocytes and cultured fibroblasts. Evidence: TAS. Frequency: Very frequent (HP:0040281). (ORPHA:206436)
- Decreased nerve conduction velocity (HP:0000762): A reduction in the speed at which electrical signals propagate along the axon of a neuron. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Hand clenching (HP:0001188): An abnormal hand posture in which the hands are clenched to fists. All digits held completely flexed at the metacarpophalangeal and interphalangeal joints. In prenatal sonography of the fetal clenched hand, the index finger overlaps a clenched fist formed by the other digits. The proximal interphalangeal articulation of the index finger is flexed and ulnarly deviated, and the thumb is adducted. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Lower limb spasticity (HP:0002061): Spasticity (velocity-dependent increase in tonic stretch reflexes with increased muscle tone and hyperexcitable tendon reflexes) in the muscles of the lower limbs, hips, and pelvis. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Psychomotor deterioration (HP:0002361): Loss of previously present mental and motor abilities. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Abnormal periventricular white matter morphology (HP:0002518): A structural abnormality of the myelinated axons (white matter) located near the cerebral ventricles. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Delayed brainstem auditory evoked response conduction time (HP:0004466): An abnormal increase (delay) in the conduction time of the brainstem auditory-evoked response. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Peripheral neuropathy (HP:0009830): Peripheral neuropathy is a general term for any disorder of the peripheral nervous system. The main clinical features used to classify peripheral neuropathy are distribution, type (mainly demyelinating versus mainly axonal), duration, and course. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Elevated brain choline level by MRS (HP:0012706): An increase in the level of choline-containing compounds in the brain identified by magnetic resonance spectroscopy (MRS). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Reduced brain N-acetyl aspartate level by MRS (HP:0012708): A decrease in the level of N-acetyl aspartate in the brain identified by magnetic resonance spectroscopy (MRS). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Reduced brain glutamate level by MRS (HP:0031161): An decrease in the level of glutamate (Glu) in the brain identified by magnetic resonance spectroscopy (MRS). Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:206436)
- Hydrocephalus (HP:0000238): Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Visual loss (HP:0000572): Loss of visual acuity (implying that vision was better at a certain time point in life). Otherwise the term reduced visual acuity should be used (or a subclass of that). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Photophobia (HP:0000613): Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Blindness (HP:0000618): Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Optic atrophy (HP:0000648): Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- 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:206436)
- 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: Occasional (HP:0040283). (ORPHA:206436)
- Hyporeflexia (HP:0001265): Reduction of neurologic reflexes such as the knee-jerk reaction. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Encephalopathy (HP:0001298): Encephalopathy is a term that means brain disease, damage, or malfunction. In general, encephalopathy is manifested by an altered mental state. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Muscle weakness (HP:0001324): Reduced strength of muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Hyperreflexia (HP:0001347): Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Weight loss (HP:0001824): Reduction of total body weight. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Vomiting (HP:0002013): Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Gastroesophageal reflux (HP:0002020): A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Respiratory distress (HP:0002098): Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Generalized myoclonic seizure (HP:0002123): A generalized myoclonic seizure is a type of generalized motor seizure characterized by bilateral, sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Opisthotonus (HP:0002179): Opisthotonus is defined as a dramatic abnormal posture due to spastic contraction of the extensor muscles of the neck, trunk, and lower extremities that produces a severe backward arching from neck to heel. In most cases, the trunk is elevated off the ground by a few inches. It is usually sudden in onset and can be sustained or repetitive. It can be considered a variant of decerebrate posturing involving a hyperextension of the neck, back, and limbs. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Poor head control (HP:0002421): Difficulty to maintain correct position of the head while standing or sitting. Infant head lag is observed when the head seems to flop around or lags posteriorly behind the trunk. Several articles have maintained that head lag should be absent by age 3 to 4 months. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Diffuse cerebral atrophy (HP:0002506): Diffuse unlocalised atrophy affecting the cerebrum. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Increased intracranial pressure (HP:0002516): An increase of the pressure inside the cranium (skull) and thereby in the brain tissue and cerebrospinal fluid. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Recurrent infections (HP:0002719): Increased susceptibility to infections as manifested by repeated bouts of infection. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Respiratory failure (HP:0002878): A severe form of respiratory insufficiency characterized by inadequate gas exchange such that the levels of oxygen or carbon dioxide cannot be maintained within normal limits. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Muscle spasm (HP:0003394): Sudden and involuntary contractions of one or more muscles. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Shoulder girdle muscle weakness (HP:0003547): The shoulder, or pectoral, girdle is composed of the clavicles and the scapulae. Shoulder-girdle weakness refers to lack of strength of the muscles attaching to these bones, that is, lack of strength of the muscles around the shoulders. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Muscle stiffness (HP:0003552): A condition in which muscles cannot be moved quickly without accompanying pain or spasm. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Cachexia (HP:0004326): Severe weight loss, wasting of muscle, loss of appetite, and general debility related to a chronic disease. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Temperature instability (HP:0005968): Disordered thermoregulation characterized by an impaired ability to maintain a balance between heat production and heat loss, with resulting instability of body temperature. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Hypointensity of cerebral white matter on MRI (HP:0007103): A darker than expected signal on magnetic resonance imaging emanating from the cerebral white matter. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Decorticate rigidity (HP:0011444): A type of rigidity in which the arms are in flexion and adduction and the legs are extended. This signifies a lesion in the cerebral white matter, internal capsules, or thalamus. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- 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:206436)
- Nasogastric tube feeding in infancy (HP:0011470): Feeding problem necessitating nasogastric tube feeding. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Decerebrate rigidity (HP:0025013): A type of rigidity that is manifested by an exaggerated extensor posture of all extremities. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Slow pupillary light response (HP:0030211): Reduced velocity and acceleration in the pupillary light response. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Abnormal heart rate variability (HP:0031860): Any abnormality in the variability of the time interval between successive heartbeats. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Increased head circumference (HP:0040194): An abnormally increased head circumference in a growing child. Head circumference is measured with a nonelastic tape and comprises the distance from above the eyebrows and ears and around the back of the head. The measured HC is then plotted on an appropriate growth chart. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Decreased head circumference (HP:0040195): An abnormally reduced head circumference in a growing child. Head circumference is measured with a nonelastic tape and comprises the distance from above the eyebrows and ears and around the back of the head. The measured HC is then plotted on an appropriate growth chart. Microcephaly is defined as a head circumference (HC) that is great than two standard deviations below the mean of age- and gender-matched population based samples. Severe microcephaly is defined with an HC that is three standard deviations below the mean. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Hyperesthesia (HP:0100963): Increased sensitivity to stimulation, excluding the special senses, which may refer to various modes of cutaneous sensibility including touch and thermal sensation without pain, as well as to pain. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:206436)
- Neck muscle weakness (HP:0000467): Decreased strength of the neck musculature. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:206436)
- Hypopigmented skin patches (HP:0001053). Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:206436)
- Spastic diplegia (HP:0001264): Spasticity (neuromuscular hypertonia) primarily in the muscles of the legs, hips, and pelvis. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:206436)
- Laryngomalacia (HP:0001601): Laryngomalacia is a congenital abnormality of the laryngeal cartilage in which the cartilage is floppy and prolapses over the larynx during inspiration. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:206436)
- Cherry red spot of the macula (HP:0010729): Pallor of the perifoveal macula of the retina with appearance of a small circular reddish choroid shape as seen through the fovea centralis due to relative transparency of the macula. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:206436)
These phenotypes are associated with the disease Infantile Krabbe disease (ORPHA:206436).