- Scaphocephaly (HP:0030799): Scaphocephaly is a subtype of dolichocephaly where the anterior and posterior aspects of the cranial vault are pointed (boat-shaped). Scaphocephaly is caused by a precocious fusion of sagittal suture without other associated synostosis. Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Type 2 muscle fiber atrophy (HP:0003554): Atrophy (wasting) affecting primary type 2 muscle fibers. This feature in general can only be observed on muscle biopsy. Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Hypsarrhythmia (HP:0002521): Hypsarrhythmia is abnormal interictal high amplitude waves and a background of irregular spikes. There is continuous (during wakefulness), high-amplitude (>200 Hz), generalized polymorphic slowing with no organized background and multifocal spikes demonstrated by electroencephalography (EEG). Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Delayed CNS myelination (HP:0002188): Delayed myelination in the central nervous system. Evidence: PCS. Frequency: 4/5. (PMID:28733338)
- Severe muscular hypotonia (HP:0006829): A severe degree of muscular hypotonia characterized by markedly reduced muscle tone. Evidence: PCS. Frequency: 5/5. (PMID:28733338)
- Blepharophimosis (HP:0000581): A fixed reduction in the vertical distance between the upper and lower eyelids with short palpebral fissures. Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Turricephaly (HP:0000262): Tall head relative to width and length. Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Type 2 muscle fiber predominance (HP:0010602): An abnormal predominance of type II muscle fibers (in general, this feature can only be observed on muscle biopsy). Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Feeding difficulties in infancy (HP:0008872): Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention. Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Death in infancy (HP:0001522): Death within the first 24 months of life. Evidence: PCS. Frequency: 5/5. (PMID:28733338)
- Wide intermamillary distance (HP:0006610): A larger than usual distance between the left and right nipple. Evidence: PCS. Frequency: 1/5. (PMID:28733338)
- EMG: decremental response of compound muscle action potential to repetitive nerve stimulation (HP:0003403): A compound muscle action potential (CMAP) is a type of electromyography (EMG). CMAP refers to a group of almost simultaneous action potentials from several muscle fibers in the same area evoked by stimulation of the supplying motor nerve and are recorded as one multipeaked summated action potential. This abnormality refers to a greater than normal decrease in the amplitude during the course of the investigation. Evidence: PCS. Frequency: 1/5. (PMID:28733338)
- Arachnodactyly (HP:0001166): Abnormally long and slender fingers (spider fingers). Evidence: PCS. Frequency: 1/5. (PMID:28733338)
- Type 1 muscle fiber atrophy (HP:0011807): Atrophy (wasting) affecting primary type 1 muscle fibers. This feature in general can only be observed on muscle biopsy. Evidence: PCS. Frequency: 2/5. (PMID:28733338)
- Cerebral atrophy (HP:0002059): Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum. Evidence: PCS. Frequency: 5/5. (PMID:28733338)
- Polyhydramnios (HP:0001561): The presence of excess amniotic fluid in the uterus during pregnancy. Evidence: PCS. Frequency: 2/5. Onset: Fetal onset (HP:0011461). (PMID:28733338)
- 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: PCS. Frequency: 1/5. (PMID:28733338)
- Thymus hyperplasia (HP:0010516): Enlargement of the thymus. Evidence: PCS. Frequency: 1/4. (PMID:28733338)
- EEG with burst suppression (HP:0010851): The burst suppression pattern in electroencephalography refers to a characteristic periodic pattern of low voltage (<10 microvolts) suppressed background and a relatively shorter pattern of higher amplitude slow, sharp, and spiking complexes. Evidence: PCS. Frequency: 3/5. (PMID:28733338)
- Chylothorax (HP:0010310): Accumulation of excessive amounts of lymphatic fluid (chyle) in the pleural cavity. Evidence: PCS. Frequency: 1/5. (PMID:28733338)
- Congenital contracture (HP:0002803): One or more flexion contractures (a bent joint that cannot be straightened actively or passively) that are present at birth. Evidence: PCS. Frequency: 3/5. Onset: Congenital onset (HP:0003577). (PMID:28733338)
- 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:28733338)
- Decreased fetal movement (HP:0001558): An abnormal reduction in quantity or strength of fetal movements. Evidence: PCS. Frequency: 5/5. Onset: Fetal onset (HP:0011461). (PMID:28733338)
- Neonatal respiratory distress (HP:0002643): Respiratory difficulty as newborn. Evidence: PCS. Frequency: 3/5. Onset: Neonatal onset (HP:0003623). (PMID:28733338)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: PCS. Frequency: 1/5. (PMID:28733338)
These phenotypes are associated with the disease myopathy, epilepsy, and progressive cerebral atrophy (OMIM:619036).