Individuals with TEC have a median age of presentation of 18–26 months; however, the disorder may occur in infants younger than 6 months and in children as old as age 10 years.

Because of the gradual onset of the anemia, children are often healthier than expected from their low hemoglobin levels.

Transient erythroblastopenia of childhood (TEC) is a slowly developing anemia of early childhood characterized by gradual onset of pallor.

People with PCH, a polyclonal IgG anti-P autoantibody binds to red blood cell surface antigens in the cold. This can occur in a susceptible individual as blood passes through cold extremities in cold weather. When the blood returns to the warmer central circulation, the red blood cells are lysed with complement, causing intravascular hemolysis. Hemoglobinuria and anemia can then occur. The anemia may be mild or severe.

Acute PCH tends to be transient and self-limited, particularly in children. Chronic PCH associated with syphilis resolves after the syphilis is treated with appropriate antibiotics. Chronic idiopathic PCH is usually mild.

Transient hypogammaglobulinemia of infancy is a form of hypogammaglobulinemia appearing after birth, leading to a reduction in the level of IgG, and also sometimes IgA and IgM. (The ratios of immunoglobulins vary rapidly in all infants, and the term dysgammaglobulinemia, although theoretically applicable, is not usually used in this context.)

It can result in increased infections, but it can also present without symptoms.

Symptoms can include:

- pallor

- tachycardia

- decreased activity

Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of anemia affecting the precursors to red blood cells but not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells. The condition has been first described by Paul Kaznelson in 1922.

North American Indian childhood cirrhosis (NAIC) is a disease in humans that can affect Ojibway-Cree children in northwestern Quebec, Canada. The disease is due to an autosomal recessive abnormality of the "CIRH1A" gene, which codes for cirhin.

NAIC is a ribosomopathy. An R565W mutation of "CIRH1A" leads to partial impairment of cirhin interaction with NOL11.

Initial transient neonatal jaundice advances over time to biliary cirrhosis with severe liver fibrosis. Eventually, liver failure occurs, and requires liver transplantation.

Transient hyperammonemia of the newborn (THAN) is an idiopathic disorder occasionally present in preterm newborns but not always symptomatic. Continuous dialysis or hemofiltration have proven to be the most effective treatment. Nutritional support and sodium benzoate have also been used to treat THAN.

Neonatal hypoglycemia is a transient or temporary condition of decreased blood sugar or hypoglycemia in a neonate.

Transient bullous dermolysis of the newborn (TBDN) is a skin condition that presents in newborns. It is characterized by blister formation secondary to even mild trauma.

It is associated with "COL7A1".

Pearson syndrome is a mitochondrial disease characterized by sideroblastic anemia and exocrine pancreas dysfunction. Other clinical features are failure to thrive, pancreatic fibrosis with insulin-dependent diabetes and exocrine pancreatic deficiency, muscle and neurologic impairment, and, frequently, early death. It is usually fatal in infancy. The few patients who survive into adulthood often develop symptoms of Kearns-Sayre syndrome.

It is caused by a deletion in mitochondrial DNA. Pearson syndrome is very rare, less than hundred cases have been reported in medical literature worldwide.

The syndrome was first described by pediatric hematologist and oncologist Howard Pearson in 1979; the deletions causing it were discovered a decade later.

Transient neonatal pustular melanosis (also known as "transient neonatal pustulosis" and "lentigines neonatorum") is a cutaneous condition that presents at birth with 1- to 3-mm flaccid, superficial fragile pustules, some of which may have already resolved in utero, leaving pigmented macules.

1. Blood. With Pearson Syndrome, the bone marrow fails to produce white blood cells called neutrophils. The syndrome also leads to anemia, low platelet count, and aplastic anemia It may be confused with transient erythroblastopenia of childhood.

2. Pancreas. Pearson Syndrome causes the exocrine pancreas to not function properly because of scarring and atrophy

Individuals with this condition have difficulty absorbing nutrients from their diet which leads to malabsorption. infants with this condition generally do not grow or gain weight.

Sneddon's syndrome generally manifests with stroke or severe, transient neurological symptoms, and a skin rash (livedo reticularis). Livedo reticularis appears as a bluish-purple, netlike mottling of the skin. Sneddon's syndrome may instead present with livedo racemosa, which involves larger, less organized patches of bluish-purple mottling of the skin. Both are generally found first in the extremities, both worsen in cold and either may occur without Sneddon's Syndrome or any other systemic disease.

Sneddon's Syndrome can be characterized by: transient amnesia, transient aphasia, palsy, headaches, hypertension, transient ischemic attacks (TIA), stroke, coronary disease and dementia. The skin manifestations may precede the neurologic symptoms by years.

The common cause is congenital, but it can also be caused by maternal steroids passed on through breast milk to the newborn. It is different from breast feeding-associated jaundice (breast-fed infants have higher bilirubin levels than formula-fed ones).

Protein C deficiency is a rare genetic trait that predisposes to thrombotic disease. It was first described in 1981. The disease belongs to a group of genetic disorders known as thrombophilias. Protein C deficiency is associated with an increased incidence of venous thromboembolism (relative risk 8–10), whereas no association with arterial thrombotic disease has been found.

Oculo-respiratory syndrome is a usually transient condition characterized by bilateral conjunctivitis, facial edema, and upper respiratory symptoms following influenza immunization. Symptoms typically appear 2 to 24 hours after vaccination and resolve within 48 hours of onset.

Temporary hypoglycemia in the first three hours after birth is a normal finding. Most of the time it resolves without medical intervention. The lowest blood sugars occur one to two hours after birth. After this time, lactose begins to be available through the breast milk. In addition, gluconeogenesis occurs when the kidneys and liver convert fats into glucose..

A symptom complex characterised by the clinical features of a high intermittent fever of septic type, constantly recurring exanthema, transient arthralgia, carditis, pleurisy, neutrophil leukocytosis, and increased erythrocyte sedimentation rate.

Sneddon's syndrome is a form of arteriopathy characterized by several symptoms, including:

- Severe, transient neurological symptoms or Stroke

- Livedo reticularis or Livedo racemosa

A defect in the UGT1A1-gene, also linked to Crigler–Najjar syndrome and Gilbert's syndrome, is responsible for the congenital form of Lucey–Driscoll syndrome.

Since the etiology is unconfirmed, diagnosis is generally accomplished when there is hyperammonemia present within 24–36 hours of birth and urea cycle defects can be excluded. Organic acidemias and other metabolic errors must also be excluded. The diagnostic criteria for hyperammonemia is ammonia blood levels higher than 35 µmol/L. This is accomplished by observing urine ketones, organic acids, enzyme levels and activities, and plasma and urine amino acids. Mild Transient Hyperammonemia is diagnosed when ammonia levels are between 40-50 µM, lasts for about 6–8 weeks, and has no related neurological problems. Severe Transient Hyperammonemia is diagnosed when ammonia levels are above 50 µM up to as much as 4000 µM. Severe Transient Hyperammonemia causes neurological problems as ammonia levels in the brain are too high, which can cause infant hyptotonia as well as neonatal seizures. Severe Transient Hyperammonemia can also cause respiratory distress syndrome. Chest x-rays may resemble hyaline membrane disease.

Morning pseudoneutropenia is a transient reduction in the measured neutrophil count from peripheral samples. This is noticed in some patients who are taking antipsychotic medication. Morning pseudoneutropenia is thought to be due to diurnal variation in the amount of circulating white blood cells and changes in the levels of hematopoietic cytokines and granulocyte colony stimulating factor (GCSF). Antipsychotics may amplify the natural variation in these hematopoietic factors.

Neutropenia is a hematological disorder characterized by an abnormally low number of neutrophils in the blood. Neutrophils usually make up 50-70% of circulating white blood cells and serve as the primary defense against infections. There is some variability in the neutrophil counts depending upon when the sample is taken, where the blood sample is taken from, and the system used by the medical lab for measuring the blood cells, but any significant reduction in function or number below the appropriate range may predispose individuals to infections.

Case reports of such incidences are reported with Clozapine and Risperidone and Aripiprazole.

These case reports suggest that the observed cases of the morning pseudoneutropenia did not proceed to become agranulocytosis which is a significant and dangerous side effect of some of antipsychotics. Hence it was suggested that although the morning neutrophil count may appear low, if the antipsychotic medication were considered efficaceous then white cell counts may be repeated in the afternoon prior to making a decision based only on the morning counts.

Chromosome 5q deletion syndrome (chromosome 5q monosomy, 5q- syndrome) is an acquired, hematological disorder characterized by loss of part of the long arm (q arm, band 5q33.1) of human chromosome 5 in bone marrow myelocyte cells. This chromosome abnormality is most commonly associated with the myelodysplastic syndrome.

It should not be confused with "partial trisomy 5q", though both conditions have been observed in the same family.

This should not be confused with the germ line cri du chat (5p deletion) syndrome which is a deletion of the short arm of the 5th chromosome.