- Exaggerated startle response (HP:0002267): An exaggerated startle reaction in response to a sudden unexpected visual or acoustic stimulus, or a quick movement near the face. Evidence: PCS. Frequency: 3/7. (PMID:36001086)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: PCS. Frequency: 6/6. (PMID:36001086)
- 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: PCS. Frequency: 1/5. (PMID:36001086)
- Hearing impairment (HP:0000365): A decreased magnitude of the sensory perception of sound. Evidence: PCS. Frequency: 3/3. (PMID:36001086)
- Cerebral cortical atrophy (HP:0002120): Atrophy of the cortex of the cerebrum. Evidence: PCS. Frequency: 1/7. (PMID:36001086)
- 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: 3/7. (PMID:36001086)
- Myoclonic seizure (HP:0032794): A myoclonic seizure is a type of motor seizure characterized by 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: PCS. Frequency: 4/4. Onset: Neonatal onset (HP:0003623). (PMID:36001086)
- Fasciculations (HP:0002380): Fasciculations are observed as small, local, involuntary muscle contractions (twitching) visible under the skin. Fasciculations result from increased irritability of an axon (which in turn is often a manifestation of disease of a motor neuron). This leads to sporadic discharges of all the muscle fibers controlled by the axon in isolation from other motor units. Evidence: PCS. Frequency: 1/7. (PMID:36001086)
- Dysgyria (HP:0032398): An abnormal gyral pattern characterized by abnormalities of sulcal depth or orientation. Evidence: PCS. Frequency: 4/7. (PMID:36001086)
- Brain atrophy (HP:0012444): Partial or complete wasting (loss) of brain tissue that was once present. Evidence: PCS. Frequency: 4/7. (PMID:36001086)
- Nystagmus (HP:0000639): Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms. Evidence: PCS. Frequency: 2/5. (PMID:36001086)
- Cataract (HP:0000518): A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule. Evidence: PCS. Frequency: 1/5. (PMID:36001086)
- Inferior cerebellar vermis hypoplasia (HP:0007068): Underdevelopment of the inferior portion of the vermis of cerebellum. Evidence: PCS. Frequency: 1/7. (PMID:36001086)
- 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: PCS. Frequency: 6/6. (PMID:36001086)
- Patent ductus arteriosus (HP:0001643): In utero, the ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta by connecting the main pulmonary artery to the descending aorta. A patent ductus arteriosus (PDA) in the first 3 days of life is a physiologic shunt in healthy term and preterm newborn infants, and normally is substantially closed within about 24 hours after bith and completely closed after about three weeks. Failure of physiologcal closure is referred to a persistent or patent ductus arteriosus (PDA). Depending on the degree of left-to-right shunting, PDA can have clinical consequences. Evidence: PCS. Frequency: 1/6. (PMID:36001086)
- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 3/7. (PMID:36001086)
- Cerebellar hypoplasia (HP:0001321): Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time. Evidence: PCS. Frequency: 1/7. (PMID:36001086)
- Limb joint contracture (HP:0003121): A contracture (chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin) that prevent normal movement of one or more joints of the limbs. Evidence: PCS. Frequency: 4/4. (PMID:36001086)
- 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: 3/3. (PMID:36001086)
- Limb hypertonia (HP:0002509). Evidence: PCS. Frequency: 4/7. (PMID:36001086)
- 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:36001086)
- Intrauterine growth retardation (HP:0001511): An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age. Evidence: PCS. Frequency: 3/7. (PMID:36001086)
- Atrial septal defect (HP:0001631): Atrial septal defect (ASD) is a congenital abnormality of the interatrial septum that enables blood flow between the left and right atria via the interatrial septum. Evidence: PCS. Frequency: 2/6. (PMID:36001086)
- Tremor (HP:0001337): An unintentional, oscillating to-and-fro muscle movement about a joint axis. Evidence: PCS. Frequency: 1/7. (PMID:36001086)
- Cryptorchidism (HP:0000028): Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum. Evidence: PCS. Frequency: 3/4. (PMID:36001086)
- Patent foramen ovale (HP:0001655): Failure of the foramen ovale to seal postnatally, leaving a potential conduit between the left and right cardiac atria. Evidence: PCS. Frequency: 1/6. (PMID:36001086)
- Hydronephrosis (HP:0000126): Severe distention of the kidney with dilation of the renal pelvis and calices. Evidence: PCS. Frequency: 1/6. (PMID:36001086)
These phenotypes are associated with the disease neurodegeneration with developmental delay, early respiratory failure, myoclonic seizures, and brain abnormalities (OMIM:620327).