Traits

Traits linked to TTC7A

tetratricopeptide repeat domain 7A

The Human Phenotype Ontology links 50 traits to TTC7A, by body system: features seen in people with one of the gene's rare conditions.

TTC7A

Abnormality of the digestive system

Trait	How often it is seen
Bloody diarrhea	Always
Enterocolitis	Always
Ileal atresia	Always
Interface hepatitis	Always
Intestinal obstruction	Always
Colonic atresia	Very often (80–99%)
Gastrointestinal atresia	Very often (80–99%)
Intestinal atresia	Very often (80–99%)
Jejunal atresia	Very often (80–99%)
Abdominal bloating	Often (30–79%)
Absence or narrowing of first part of small bowel	Often (30–79%)
Jejunoileal ulceration	Often (30–79%)
Rectal atresia	Often (30–79%)
Abnormal ductus choledochus morphology	Sometimes (5–29%)
Intestinal malrotation	Sometimes (5–29%)
Omphalocele	Sometimes (5–29%)
Peritoneal abscess	Sometimes (5–29%)
Rectal abscess	Sometimes (5–29%)
Liver inflammation	Rarely (1–4%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Elevated white blood count	Always
Increased number of platelets in blood	Always
T-cell lymphoma	Always
Decreased blood lymphocyte number	Often (30–79%)
Rectal bleeding	Often (30–79%)
Autoimmune hemolytic anemia	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Recurrent respiratory infections	Always
Severe combined immunodeficiency	Very often (80–99%)
Decreased immune function	Often (30–79%)
Autoimmunity	Sometimes (5–29%)
Psoriasiform dermatitis	Sometimes (5–29%)
Recurrent abscess formation	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Prominent forehead	Always
Thin dental enamel	Always
Absent eyebrow	Often (30–79%)
Absence of scalp hair	Sometimes (5–29%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased circulating antibody level	Often (30–79%)
Impaired phytohemagglutinin-induced T lymphocyte transformation	Often (30–79%)
Agammaglobulinemia	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Sparse hair	Often (30–79%)
Thickened skin	Sometimes (5–29%)
Poor nail formation	Rarely (1–4%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Often (30–79%)
Congenital pulmonary airway malformation	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Hole in heart wall separating two lower heart chambers	Sometimes (5–29%)
Small thymus	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Hashimoto thyroiditis	Rarely (1–4%)

Abnormality of the eye

Trait	How often it is seen
Wide-set eyes	Always

Abnormality of the musculoskeletal system

Trait	How often it is seen
Ectopic calcification	Very often (80–99%)

Growth abnormality

Trait	How often it is seen
Prenatal growth deficiency	Often (30–79%)

Laboratory abnormality

Trait	How often it is seen
Type 1 diabetes	Rarely (1–4%)

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to TTC7A and how often each is seen. Find out more at hpo.jax.org.

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