MedGen

Aceruloplasminemia is characterized by iron accumulation in the brain and viscera. The clinical triad of retinal degeneration, diabetes mellitus (DM), and neurologic disease is seen in individuals ranging from age 30 years to older than 70 years. The neurologic findings of movement disorder (blepharospasm, grimacing, facial and neck dystonia, tremors, chorea) and ataxia (gait ataxia, dysarthria) correspond to regions of iron deposition in the brain. Individuals with aceruloplasminemia often present with anemia prior to onset of DM or obvious neurologic problems. Cognitive dysfunction including apathy and forgetfulness occurs in more than half of individuals with this condition. [from GeneReviews]

Trichohepatoenteric syndrome (THES), generally considered to be a neonatal enteropathy, is characterized by intractable diarrhea (seen in almost all affected children), woolly hair (seen in all), intrauterine growth restriction, facial dysmorphism, and short stature. Additional findings include poorly characterized immunodeficiency, recurrent infections, skin abnormalities, and liver disease. Mild intellectual disability (ID) is seen in about 50% of affected individuals. Less common findings include congenital heart defects and platelet anomalies. To date 52 affected individuals have been reported. [from GeneReviews]

A rare genetic primary immunodeficiency with characteristics of increased susceptibility to fungal infections that typically manifest as recurrent, chronic mucocutaneous candidiasis, systemic candidiasis with meningoencephalitis and deep dermatophytosis. Dermatophytes invade skin, hair, nails, lymph nodes and brain, resulting in erythematosquamous lesions, nodular subcutaneous or ulcerative infiltrations, severe onychomycosis and lymphadenopathy. [from SNOMEDCT_US]

Features that occur less commonly in people with TRNT1 deficiency include hearing loss caused by abnormalities of the inner ear (sensorineural hearing loss), recurrent seizures (epilepsy), and problems with the kidneys or heart.

TRNT1 deficiency encompasses what was first thought to be two separate disorders, a severe disorder called sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay (SIFD) and a milder disorder called retinitis pigmentosa with erythrocytic microcytosis (RPEM), each named for its most common features. SIFD begins in infancy, and affected individuals usually do not survive past childhood. RPEM, on the other hand, is recognized in early adulthood, and the microcytosis usually does not cause any health problems. However, it has since been recognized that some individuals have a combination of features that fall between these two ends of the severity spectrum. All of these cases are now considered part of TRNT1 deficiency.

Neurological problems are also frequent in TRNT1 deficiency. Many affected individuals have delayed development of speech and motor skills, such as sitting, standing, and walking, and some have low muscle tone (hypotonia).

Eye abnormalities, often involving the light-sensing tissue at the back of the eye (the retina), can occur in people with TRNT1 deficiency. Some of these individuals have a condition called retinitis pigmentosa, in which the light-sensing cells of the retina gradually deteriorate. Eye problems in TRNT1 deficiency can lead to vision loss.

In addition, many individuals with TRNT1 deficiency have recurrent fevers that are not caused by an infection. These fever episodes are often one of the earliest recognized symptoms of TRNT1 deficiency, usually beginning in infancy. The fever episodes are typically accompanied by poor feeding, vomiting, and diarrhea, and can lead to hospitalization. In many affected individuals, the episodes occur regularly, arising approximately every 2 to 4 weeks and lasting 5 to 7 days, although the frequency can decrease with age.

Many people with TRNT1 deficiency have an immune system disorder (immunodeficiency) that can lead to recurrent bacterial infections. Repeated infections can cause life-threatening damage to internal organs. The immunodeficiency is characterized by low numbers of immune system cells called B cells, which normally help fight infections by producing immune proteins called antibodies (or immunoglobulins). These proteins target foreign invaders such as bacteria and viruses and mark them for destruction. In many individuals with TRNT1 deficiency, the amount of immunoglobulins is also low (hypogammaglobulinemia).

A common feature of TRNT1 deficiency is a blood condition called sideroblastic anemia, which is characterized by a shortage of red blood cells (anemia). In TRNT1 deficiency, the red blood cells that are present are unusually small (erythrocytic microcytosis). In addition, developing red blood cells in the bone marrow (erythroblasts) can have an abnormal buildup of iron that appears as a ring of blue staining in the cell after treatment in the lab with certain dyes. These abnormal cells are called ring sideroblasts.

TRNT1 deficiency is a condition that affects many body systems. Its signs and symptoms can involve blood cells, the immune system, the eyes, and the nervous system. The severity of the signs and symptoms vary widely. [from MedlinePlus Genetics]

The concentration of iron in the blood circulation is below the lower limit of normal. [from HPO]