- Neonatal alloimmune thrombocytopenia (HP:0004809): Low platelet count associated with maternal platelet-specific alloantibodies. Evidence: TAS. Frequency: Obligate (HP:0040280). (ORPHA:853)
- Petechiae (HP:0000967): Petechiae are pinpoint-sized reddish/purple spots, resembling a rash, that appear just under the skin or a mucous membrane when capillaries have ruptured and some superficial bleeding into the skin has happened. This term refers to an abnormally increased susceptibility to developing petechiae. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:853)
- Purpura (HP:0000979): Purpura (from Latin: purpura, meaning purple) is the appearance of red or purple discolorations on the skin that do not blanch on applying pressure. They are caused by bleeding underneath the skin. This term refers to an abnormally increased susceptibility to developing purpura. Purpura are larger than petechiae. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:853)
- Abnormal bleeding (HP:0001892): An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:853)
- Spontaneous hematomas (HP:0007420): Spontaneous development of hematomas (hematoma) or bruises without significant trauma. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:853)
- Cephalohematoma (HP:0012541): Hemorrhage between the skull and periosteum of a newborn resulting from rupture of blood vessels that cross the periosteum. Evidence: TAS. Frequency: Frequent (HP:0040282). (ORPHA:853)
- Hematuria (HP:0000790): The presence of blood in the urine. Hematuria may be gross hematuria (visible to the naked eye) or microscopic hematuria (detected by dipstick or microscopic examination of the urine). Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:853)
- Intracranial hemorrhage (HP:0002170): Hemorrhage occurring within the skull. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:853)
- Gastrointestinal hemorrhage (HP:0002239): Hemorrhage affecting the gastrointestinal tract. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:853)
- Melena (HP:0002249): The passage of blackish, tarry feces associated with gastrointestinal hemorrhage. Melena occurs if the blood remains in the colon long enough for it to be broken down by colonic bacteria. One degradation product, hematin, imbues the stool with a blackish color. Thus, melena generally occurs with bleeding from the upper gastrointestinal tract (e.g., stomach ulcers or duodenal ulcers), since the blood usually remains in the gut for a longer period of time than with lower gastrointestinal bleeding. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:853)
- Ecchymosis (HP:0031364): A purpuric lesion that is larger than 1 cm in diameter. Evidence: TAS. Frequency: Occasional (HP:0040283). (ORPHA:853)
- Blindness (HP:0000618): Blindness is the condition of lacking visual perception defined as a profound reduction in visual perception. On the 6m visual acuity scale, blindness is defined as less than 3/60. On the 20ft visual acuity scale, blindness is defined as less than 20/400. On the decimal visual acuity scale, blindness is defined as less than 0.05. Blindness is typically characterized by a visual field of no greater than 10 degrees in radius around central fixation. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:853)
- Abnormality of the nervous system (HP:0000707): An abnormality of the nervous system. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:853)
- 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: TAS. Frequency: Very rare (HP:0040284). (ORPHA:853)
- Subarachnoid hemorrhage (HP:0002138): Hemorrhage occurring between the arachnoid mater and the pia mater. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:853)
- Bilateral sensorineural hearing impairment (HP:0008619): A form of sensorineural hearing impairment that affects both ears. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:853)
- Cerebral palsy (HP:0100021): Cerebral palsy describes a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to nonprogressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of cerebral palsy are often accompanied by disturbances of sensation, perception, cognition, communication, and behavior, by epilepsy, and by secondary musculoskeletal problems. Evidence: TAS. Frequency: Very rare (HP:0040284). (ORPHA:853)
These phenotypes are associated with the disease Fetal and neonatal alloimmune thrombocytopenia (ORPHA:853).