- Brachydactyly (HP:0001156): Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here. Evidence: PCS. (PMID:32220290)
- Long face (HP:0000276): Facial height (length) is more than 2 standard deviations above the mean (objective); or, an apparent increase in the height (length) of the face (subjective). Evidence: PCS. (PMID:32220290)
- 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: 10/12. (PMID:32220290)
- 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: PCS. Frequency: 4/8. (PMID:32220290)
- Elevated circulating alkaline phosphatase concentration (HP:0003155): Abnormally increased serum levels of alkaline phosphatase activity. Evidence: PCS. Frequency: 0/10. (PMID:32220290)
- 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: 12/12. (PMID:32220290)
- Ataxia (HP:0001251): Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly). Evidence: PCS. Frequency: 5/12. (PMID:32220290)
- Infantile onset (HP:0003593): Onset of signs or symptoms of disease between 28 days to one year of life. Evidence: PCS. (PMID:32220290)
- Generalized hypotonia (HP:0001290): Generalized muscular hypotonia (abnormally low muscle tone). Evidence: PCS. Frequency: 12/12. (PMID:32220290)
- Decreased circulating alkaline phosphatase activity (HP:0003282): Concentration or activity of alkaline phosphatase outside the upper or lower limtis of normal in the blood circulation. Evidence: PCS. Frequency: 2/10. (PMID:32220290)
- Decreased expression of GPI-anchored proteins on the cell surface (HP:0041048): A decrease in the protein expression of GPI-anchor proteins, such as CD55 and CD59, at the cell surface, which suggests a defect in GPI-anchor biosynthesis. Evidence: PCS. (PMID:32220290)
- High anterior hairline (HP:0009890): Distance between the hairline (trichion) and the glabella (the most prominent point on the frontal bone above the root of the nose), in the midline, more than two SD above the mean. Alternatively, an apparently increased distance between the hairline and the glabella. Evidence: PCS. (PMID:32220290)
- Prominent antitragus (HP:0008593): Increased anterosuperior prominence of the area between the bottom of the incisura and the inner margin of the antihelix. Evidence: PCS. (PMID:32220290)
- Prominent forehead (HP:0011220): Forward prominence of the entire forehead, due to protrusion of the frontal bone. Evidence: PCS. (PMID:32220290)
- 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. (PMID:32220290)
- Dental crowding (HP:0000678): Changes in alignment of teeth in the dental arch. Evidence: PCS. (PMID:32220290)
- Thin upper lip vermilion (HP:0000219): Height of the vermilion of the upper lip in the midline more than 2 SD below the mean. Alternatively, an apparently reduced height of the vermilion of the upper lip in the frontal view (subjective). Evidence: PCS. (PMID:32220290)
- Sparse lateral eyebrow (HP:0005338): Decreased density/number and/or decreased diameter of lateral eyebrow hairs. Evidence: PCS. (PMID:32220290)
These phenotypes are associated with the disease neurodevelopmental disorder with hypotonia and cerebellar atrophy, with or without seizures (OMIM:618879).