Rare diseases · Sign or symptom
Anal atresia
Absent anus
HP:0002023
What it means
Congenital absence of the anus, i.e., the opening at the bottom end of the intestinal tract.
Rare diseases that can present with this88
Very common80–99%
13- 46,XX difference of sex development-anorectal anomalies syndrome
- Axial mesodermal dysplasia spectrum
- Cat-eye syndrome
- Craniosynostosis-anal anomalies-porokeratosis syndrome
- Lowe-Kohn-Cohen syndrome
- Nijmegen breakage syndrome
- Penile agenesis
- Short stature-wormian bones-dextrocardia syndrome
- Sirenomelia
- Syndactyly-telecanthus-anogenital and renal malformations syndrome
- Townes-Brocks syndrome
- VACTERL/VATER association
- VACTERL with hydrocephalus
Common30–79%
18- Absence deformity of leg-cataract syndrome
- Absent radius-anogenital anomalies syndrome
- Atrioventricular defect-blepharophimosis-radial and anal defect syndrome
- Caudal regression syndrome
- Cloacal exstrophy
- Currarino syndrome
- Diphallia
- Focal facial dermal dysplasia type III
- Fraser syndrome
- Holoprosencephaly-postaxial polydactyly syndrome
- Johanson-Blizzard syndrome
- LUMBAR syndrome
- Pallister-Hall syndrome
- Tetraamelia-multiple malformations syndrome
- Thakker-Donnai syndrome
- Trisomy 18 syndrome
- XK aprosencephaly syndrome
- X-linked female restricted facial dysmorphism-short stature-choanal atresia-intellectual disability
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Imperforate anus
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.