- Axial hypotonia (HP:0008936): Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Cerebellar vermis hypoplasia (HP:0001320): Underdevelopment of the vermis of cerebellum. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Sloping forehead (HP:0000340): Inclination of the anterior surface of the forehead from the vertical more than two standard deviations above the mean (objective); or apparently excessive posterior sloping of the forehead in a lateral view. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Congenital onset (HP:0003577): A phenotypic abnormality that is present at birth. Evidence: TAS. (OMIM:607196)
- 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: TAS. (OMIM:607196)
- 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. (OMIM:607196)
- Poor suck (HP:0002033): An inadequate sucking reflex, resulting in the difficult of newborns to be breast-fed. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Hepatomegaly (HP:0002240): Abnormally increased size of the liver. Evidence: TAS. (OMIM:607196)
- Failure to thrive (HP:0001508): Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Second trimester onset (HP:0034198): This term refers to a phenotypic feature that was first observed prior to birth during the second trimester, which comprises the range of gestational ages from 14 0/7 weeks to 27 6/7 (inclusive). Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- 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: PCS. Frequency: 1/1. (PMID:20583149)
- Cerebral visual impairment (HP:0100704): A form of loss of vision caused by damage to the visual cortex rather than a defect in the eye. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Primary microcephaly (HP:0011451): Head circumference below 2 standard deviations below the mean for age and gender at birth. Evidence: PCS. Frequency: 11/11. (PMID:12185364;PMID:20583149)
- Limb hypertonia (HP:0002509). Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Hypoplasia of the fovea (HP:0007750): Underdevelopment of the fovea centralis. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Partial agenesis of the corpus callosum (HP:0001338): A partial failure of the development of the corpus callosum. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- 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:12185364)
- 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: PCS. Frequency: 1/1. (PMID:20583149)
- Small anterior fontanelle (HP:0000237): Abnormally decreased size of the anterior fontanelle with respect to age-dependent norms. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Micrognathia (HP:0000347): Developmental hypoplasia of the mandible. Evidence: TAS. (OMIM:607196)
- Myoclonus (HP:0001336): Very brief, involuntary random muscular contractions occurring at rest, in response to sensory stimuli, or accompanying voluntary movements. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
- Lactic acidosis (HP:0003128): An abnormal buildup of lactic acid in the body, leading to acidification of the blood and other bodily fluids. Evidence: PCS. Frequency: 1/1. (PMID:20583149)
These phenotypes are associated with the disease Amish lethal microcephaly (OMIM:607196).