Borderline Intellectual Functioning

The term borderline intellectual functioning describes a group of people who function on the border between normal intellectual functioning and intellectual disability, between 1 and 2 standard deviations below the mean on the normal curve of the distribution of intelligence, roughly an IQ between 70 and 85.


Cluster Number:
Wiki Number: W025
Diagnosis: (Borderline) Intellectual Disability
US Patients: US2-3%
World Patients:
Sex Ratio:
Age Onset: Age5
Brain Area:
Symptoms: (IQ below 70.) includes Down Syndrome; may learn like others up to age 12
Causes: Trisomy 21-3 sets of the 21st chromosome 21 produces intellectual difficulties
Medications: None
Therapies: Behavioral training, group-home living and sheltered workshops.


The world-wide medical research
reports chosen for each diagnosis 

Clicking each title opens the
PubMed article’s summary-abstract.

  • Analysing trends of psychiatric disorders, treatment and service use across time in adults with borderline intellectual impairment: A cross-sectional study of private households
    by Amanda Lim on May 9, 2022

    While there is evidence that mental health problems are more prevalent in people with borderline intellectual functioning (BIF) compared to the general population, it is not known to what extent this has varied or changed over time and whether there have been changes in access to services. This paper compares the prevalence rates of psychiatric disorders and monitors trends in treatment and services in this population compared to the general population. We conducted secondary analysis on the...

  • Variants in PHF8 cause a spectrum of X-linked neurodevelopmental disorders and facial dysmorphology
    by Andrew K Sobering on April 26, 2022

    Loss-of-function variants in PHD Finger Protein 8 (PHF8) cause Siderius X-linked intellectual disability (ID) syndrome, hereafter called PHF8-XLID. PHF8 is a histone demethylase that is important for epigenetic regulation of gene expression. PHF8-XLID is an under-characterized disorder with only five previous reports describing different PHF8 predicted loss-of-function variants in eight individuals. Features of PHF8-XLID include ID and craniofacial dysmorphology. In this report we present 16...

  • Mental health problems in children with intellectual disability
    by Vasiliki Totsika on April 14, 2022

    Intellectual disability ranks in the top ten causes of disease burden globally and is the top cause in children younger than 5 years. 2-3% of children have an intellectual disability, and about 15% of children present with differences consistent with an intellectual disability (ie, global developmental delay and borderline intellectual functioning). In this Review, we discuss the prevalence of mental health problems, interventions to address these, and issues of access to treatment and services....

  • Germline variants in tumor suppressor FBXW7 lead to impaired ubiquitination and a neurodevelopmental syndrome
    by Sarah E M Stephenson on April 8, 2022

    Neurodevelopmental disorders are highly heterogenous conditions resulting from abnormalities of brain architecture and/or function. FBXW7 (F-box and WD-repeat-domain-containing 7), a recognized developmental regulator and tumor suppressor, has been shown to regulate cell-cycle progression and cell growth and survival by targeting substrates including CYCLIN E1/2 and NOTCH for degradation via the ubiquitin proteasome system. We used a genotype-first approach and global data-sharing platforms to...