- Mutism (HP:0002300): Complete lack of speech or verbal communication in a person despite attempts to engage in conversation. Mutism as a phenomena assumes the individual has previous capacity for speech and in the pediatric population it assumes that the person is past the age of typical language development. Evidence: IEA. (OMIM:611890)
- Peripheral axonal neuropathy (HP:0003477): An abnormality characterized by disruption of the normal functioning of peripheral axons. Evidence: IEA. (OMIM:611890)
- Abnormal anterior horn cell morphology (HP:0006802): Any anomaly of the anterior horn cell. Evidence: IEA. (OMIM:611890)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: IEA. (OMIM:611890)
- Inability to walk (HP:0002540): Incapability to ambulate. Evidence: IEA. (OMIM:611890)
- 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: IEA. Frequency: Very rare (HP:0040284). (OMIM:611890)
- 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: IEA. Frequency: Very rare (HP:0040284). (OMIM:611890)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: IEA. (OMIM:611890)
- Motor delay (HP:0001270): A type of Developmental delay characterized by a delay in acquiring motor skills. Evidence: IEA. (OMIM:611890)
- Prominent forehead (HP:0011220): Forward prominence of the entire forehead, due to protrusion of the frontal bone. Evidence: IEA. (OMIM:611890)
- Variable expressivity (HP:0003828): A variable severity of phenotypic features. Evidence: IEA. (OMIM:611890)
- Single transverse palmar crease (HP:0000954): The distal and proximal transverse palmar creases are merged into a single transverse palmar crease. Evidence: IEA. (OMIM:611890)
- Facial diplegia (HP:0001349): Facial diplegia refers to bilateral facial palsy (bilateral facial palsy is much rarer than unilateral facial palsy). Evidence: IEA. (OMIM:611890)
- 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: IEA. (OMIM:611890)
- Fetal akinesia sequence (HP:0001989): Decreased fetal activity associated with multiple joint contractures, facial anomalies and pulmonary hypoplasia. Ultrasound examination may reveal polyhydramnios, ankylosis, scalp edema, and decreased chest movements (reflecting pulmonary hypoplasia). Evidence: TAS. (OMIM:611890)
- 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: IEA. (OMIM:611890)
- Retrognathia (HP:0000278): An abnormality in which the mandible is mislocalised posteriorly. Evidence: IEA. (OMIM:611890)
- Brisk reflexes (HP:0001348): Tendon reflexes that are noticeably more active than usual (conventionally denoted 3+ on clinical examination). Brisk reflexes may or may not indicate a neurological lesion. They are distinguished from hyperreflexia by the fact that hyerreflexia is characterized by hyperactive repeating (clonic) reflexes, which are considered to be always abnormal. Evidence: IEA. (OMIM:611890)
- Skeletal muscle atrophy (HP:0003202): The presence of skeletal muscular atrophy (which is also known as amyotrophy). Evidence: TAS. (OMIM:611890)
- Myopathic facies (HP:0002058): A facial appearance characteristic of myopathic conditions. The face appears expressionless with sunken cheeks, bilateral ptosis, and inability to elevate the corners of the mouth, due to muscle weakness. Evidence: IEA. (OMIM:611890)
- 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: IEA. (OMIM:611890)
- Downslanted palpebral fissures (HP:0000494): The palpebral fissure inclination is more than two standard deviations below the mean. Evidence: IEA. (OMIM:611890)
- Microcephaly (HP:0000252): Head circumference below 2 standard deviations below the mean for age and gender. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:611890)
- Cerebral atrophy (HP:0002059): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: IEA. Frequency: Very rare (HP:0040284). (OMIM:611890)
- Hip dysplasia (HP:0001385): The presence of developmental dysplasia of the hip. Evidence: IEA. (OMIM:611890)
- Talipes equinovarus (HP:0001762): Talipes equinovarus (also called clubfoot) typically has four main components: inversion and adduction of the forefoot; inversion of the heel and hindfoot; equinus (limitation of extension) of the ankle and subtalar joint; and internal rotation of the leg. Evidence: IEA. (OMIM:611890)
- Scoliosis (HP:0002650): The presence of an abnormal lateral curvature of the spine. Evidence: IEA. (OMIM:611890)
- Gait disturbance (HP:0001288): The term gait disturbance can refer to any disruption of the ability to walk. Evidence: IEA. (OMIM:611890)
- Feeding difficulties (HP:0011968): Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it. Evidence: IEA. (OMIM:611890)
- 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: IEA. (OMIM:611890)
- Short neck (HP:0000470): Diminished length of the neck. Evidence: TAS. (OMIM:611890)
- Rocker bottom foot (HP:0001838): The presence of both a prominent heel and a convex contour of the sole. Evidence: IEA. (OMIM:611890)
- Kyphosis (HP:0002808): Exaggerated anterior convexity of the thoracic vertebral column. Evidence: IEA. (OMIM:611890)
- Ptosis (HP:0000508): The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective). Evidence: IEA. (OMIM:611890)
- Paucity of anterior horn motor neurons (HP:0007277). Evidence: TAS. (OMIM:611890)
- 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: TAS. (OMIM:611890)
- Arthrogryposis multiplex congenita (HP:0002804): Multiple congenital contractures in different body areas. Evidence: TAS. (OMIM:611890)
- Respiratory insufficiency due to muscle weakness (HP:0002747). Evidence: IEA. (OMIM:611890)
- Neonatal death (HP:0003811): Death within the first 28 days of life. Evidence: TAS. (OMIM:611890)
- Low-set ears (HP:0000369): Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear. Evidence: TAS. (OMIM:611890)
- 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: IEA. (OMIM:611890)
- Myopia (HP:0000545): An abnormality of refraction characterized by the ability to see objects nearby clearly, while objects in the distance appear blurry. Evidence: IEA. (OMIM:611890)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: IEA. (OMIM:611890)
- Areflexia of lower limbs (HP:0002522): Inability to elicit tendon reflexes in the lower limbs. Evidence: IEA. (OMIM:611890)
These phenotypes are associated with the disease lethal arthrogryposis-anterior horn cell disease syndrome (OMIM:611890).