Rare diseases · Sign or symptom
Moderate intellectual disability
IQ between 34 and 49
HP:0002342
What it means
Moderate intellectual disability (ID) is defined as a type of ID characterized by moderately sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 35-49.
Rare diseases that can present with this137
Very common80–99%
36- 16p11.2p12.2microdeletion syndrome
- 2p15p16.1microdeletion syndrome
- 2p21microdeletion syndrome
- 8q24.3microdeletion syndrome
- Ahmad syndrome
- Aicardi syndrome
- Aniridia-intellectual disability syndrome
- Ataxia-intellectual disability-oculomotor apraxia-cerebellar cysts syndrome
- Branchioskeletogenital syndrome
- Craniosynostosis-hydrocephalus-Arnold-Chiari malformation type I-radioulnar synostosis syndrome
- Deafness-intellectual disability syndrome, Martin-Probst type
- Fragile X syndrome
- Fried syndrome
- Frontonasal dysplasia-alopecia-genital anomalies syndrome
- Gómez-López-Hernández syndrome
- Hypomyelination-congenital cataract syndrome
- Infantile multisystem neurologic-endocrine-pancreatic disease
- Intellectual disability-dysmorphism-hypogonadism-diabetes mellitus syndrome
- Joubert syndrome with hepatic defect
- Lesch-Nyhan syndrome
- Moebius syndrome-axonal neuropathy-hypogonadotropic hypogonadism syndrome
- Mosaic trisomy 8 syndrome
- Pitt-Hopkins syndrome
- Rapid-onset childhood obesity-hypothalamic dysfunction-hypoventilation-autonomic dysregulation syndrome
- Retinitis pigmentosa-juvenile cataract-short stature-intellectual disability syndrome
- TMEM70-related mitochondrial encephalo-cardio-myopathy
- X-linked female restricted facial dysmorphism-short stature-choanal atresia-intellectual disability
- X-linked intellectual disability, Armfield type
- X-linked intellectual disability, Cabezas type
- X-linked intellectual disability-cubitus valgus-dysmorphism syndrome
- X-linked intellectual disability-hypogammaglobulinemia-progressive neurological deterioration syndrome
- X-linked intellectual disability-macrocephaly-macroorchidism syndrome
- X-linked intellectual disability, Najm type
- X-linked intellectual disability, Shashi type
- X-linked intellectual disability, Stevenson type
- Xp22.13p22.2duplication syndrome
Common30–79%
43- 13q12.3microdeletion syndrome
- 16q24.3microdeletion syndrome
- 19p13.3microduplication syndrome
- 20q11.2microduplication syndrome
- 3-phosphoserine phosphatase deficiency, infantile/juvenile form
- 7q11.23microduplication syndrome
- ANK3-related intellectual disability-sleep disturbance syndrome
- Autosomal recessive ataxia due to ubiquinone deficiency
- Autosomal recessive cerebellar ataxia due to CWF19L1 deficiency
- Bilateral polymicrogyria
- Cerebello-oculo-facio-genital syndrome
- Cerebrofacioarticular syndrome
- CLCN4-related X-linked intellectual disability syndrome
- Coffin-Siris syndrome
- Developmental delay-facial dysmorphism syndrome due to MED13L deficiency
- Distal duplication 5q syndrome
- Distal limb deficiencies-micrognathia syndrome
- DPAGT1-CDG
- FBLN1-related developmental delay-central nervous system anomaly-syndactyly syndrome
- FG syndrome type 1
- Floating-Harbor syndrome
- FOXP1 Syndrome
- Gabriele-de Vries syndrome
- Houge-Janssens syndrome type 1
- HSD10 disease
- Hyperinsulinism-hyperammonemia syndrome
- Intellectual disability-facial dysmorphism-hand anomalies syndrome
- Laryngeal abductor paralysis-intellectual disability syndrome
- Lethal ataxia with deafness and optic atrophy
- Malan overgrowth syndrome
- Microcephaly-glomerulonephritis-marfanoid habitus syndrome
- Microcephaly-intellectual disability-sensorineural hearing loss-epilepsy-abnormal muscle tone syndrome
- Microphthalmia with limb anomalies
- MORM syndrome
- Mowat-Wilson syndrome
- MYT1L-related developmental delay-intellectual disability-obesity syndrome
- Neurodevelopmental disorder-craniofacial dysmorphism-cardiac defect-skeletal anomalies syndrome due to 9q21.3 microdeletion
- Neurodevelopmental disorder-craniofacial dysmorphism-cardiac defect-skeletal anomalies syndrome due to a point mutation
- Partington syndrome
- Pelizaeus-Merzbacher disease, transitional form
- PGM3-CDG
- Polyendocrine-polyneuropathy syndrome
- Prader-Willi syndrome due to paternal 15q11q13 deletion
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: Intellectual disability, moderate · Mental retardation, moderate · Moderate mental deficiency · Moderate mental retardation
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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.