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No HPO annotations are available for this condition.
Int22h1/int22h2-mediated Xq28 duplication syndrome, also referred to as distal Xq28 duplication syndrome, is commonly characterized by cognitive impairment, neurobehavioral abnormalities, a combination of recurrent sinopulmonary infections (e.g., otitis media, sinusitis, recurrent upper respiratory tract infections) and atopic conditions (i.e., asthma, allergic rhinitis, and eczema), obesity, and nonspecific facial dysmorphic features (see and ). However, and both reported several adult males with this duplication who had no discernable cognitive or neurobehavioral manifestations, suggesting that this duplication may display reduced penetrance with respect to cognition and neurobehaviors. Most heterozygous females are clinically unaffected or have inconspicuous abnormalities.
For the purposes of this GeneReview, the terms "male" and "female" are narrowly defined as the individual's biological sex at birth as it determines clinical care .
Int22h1/int22h2-mediated Xq28 duplication syndrome should be considered in males with the following clinical findings and family history:
Source: GeneReviews — "Xq28 Duplication Syndrome, Int22h1/Int22h2 Mediated"
No approved treatments are currently available for chromosome Xq28 duplication syndrome. The disease remains an area of unmet medical need.
No clinical practice guidelines for int22h1/int22h2-mediated Xq28 duplication have been published. In the absence of published guidelines, the following recommendations are based on the authors' personal experience managing individuals with this disorder. Although the features of int22h1/int22h2-mediated Xq28 duplication syndrome are typically more pronounced in affected males compared to heterozygous females, affected males and heterozygous females with suggestive clinical findings including neurobehavioral abnormalities and language delays are managed with a similar clinical approach. Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with int22h1/int22h2-mediated Xq28 duplication, the evaluations summarized (if not performed as part of the evaluation that led to diagnosis) are recommended. Table 4. Int22h1/Int22h2-Mediated Xq28 Duplication Syndrome: Recommended Evaluations Following Initial Diagnosis
To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 6. Int22h1/Int22h2-Mediated Xq28 Duplication Syndrome: Recommended Surveillance
No clinical trials have been registered for chromosome Xq28 duplication syndrome.
3 publications have been identified in PubMed for chromosome Xq28 duplication syndrome. Research spans Case Report / Case Series (67%) and Review / Meta-Analysis (33%).
Zhang Y (2026). [PMID: 41622244](https://pubmed.ncbi.nlm.nih.gov/41622244/). *Molecular cytogenetics*. [Case Report / Case Series]
Németh Z (2025). [PMID: 39987543](https://pubmed.ncbi.nlm.nih.gov/39987543/). *Orvosi hetilap*. [Case Report / Case Series]
Paprocka J (2024). [PMID: 38837855](https://pubmed.ncbi.nlm.nih.gov/38837855/). *Epilepsia open*. [Review / Meta-Analysis]
Data assembled from 4 of 12 sources · Last updated Sep 19, 2026, 6:58 PM UTC
Online Mendelian Inheritance in Man
Genetic and Rare Diseases Info Center
Common questions about chromosome Xq28 duplication syndrome
Source: GeneReviews — "Xq28 Duplication Syndrome, Int22h1/Int22h2 Mediated"
Because the phenotypic features associated with int22h1/int22h2-mediated Xq28 duplication syndrome are not sufficient on their own to make a diagnosis of the condition, all disorders with intellectual disability without specific distinctive features should be considered in the differential diagnosis. See OMIM Phenotypic Series for genes associated with:
Syndromic X-linked intellectual developmental disorders;
Nonsyndromic X-linked intellectual developmental disorders;
Autosomal dominant intellectual developmental disorders;
Autosomal recessive intellectual developmental disorders.
Source: GeneReviews — "Xq28 Duplication Syndrome, Int22h1/Int22h2 Mediated"
System/Concern | Evaluation | Comment |
|---|---|---|
Anthropometrics | Measurement of weight, length/height, head circumference | For those w/obesity, consider referral to nutritionist dietician. |
Neurodevelopmental milestones cognition | Age-appropriate neurodevelopmental cognitive assessments | Neurodevelopmental milestone assessment should incl motor, cognitive, speech-language eval.; Early identification of neurodevelopmental delays would allow for early intervention. |
Neurobehavioral psychiatric abnormalities | Neuropsychiatric evals1 | For persons age ≥12 mos, screen for neurobehaviorial concerns such as aggression, irritability, emotional lability, self-mutilation, motor tics, /or findings suggestive of ASD, based on individual presentation. |
Sleep | Consider consulting sleep specialist for possible sleep study. | — |
Musculoskeletal | Assessment of spine vertebrae via spinal radiographs to detect features incl abnormal spinal curvature (e.g., kyphoscoliosis) | If kyphoscoliosis is identified, consider referral to orthopedist PT for mgmt. |
Allergy/Immunology (for males) | Screen for recurrent infections atopy,2 esp in affected males. | Incl history of recurrent severe or protracted sinopulmonary infections comorbid atopic conditions (asthma, allergic rhinitis, or eczema) |
Hearing | Audiologic eval | Assess for hearing loss. |
Vision | Ophthalmologic eval | Assess for strabismus, myopia, astigmatism. |
Genitourinary | Eval for cryptorchidism, hypospadias, or micropenis in males | If present, consider referral to pediatric urologist /or pediatric endocrinologist. |
Cardiovascular | Consider echocardiography. | To assess for congenital heart defects Genetic |
counseling | By genetics professionals3 | To obtain a pedigree inform affected persons their families or caregivers re nature, MOI, implications of int22h1/int22h2-mediated Xq28 duplication syndrome to allow for informed decision making in medical care, as well as future family planning Family support |
resources | Help connect affected person /or their families w/other affected persons families. | Assessment of family social structure to determine need for:; Community or such as Parent to Parent; Social work involvement for parental support; Home nursing referral ASD = autism spectrum disorder; MOI = mode of inheritance; PT = physical therapist For psychiatric conditions (e.g. |
Int22h1/Int22h2-Mediated Xq28 Duplication Syndrome: Treatment of Manifestations Manifestation/Concern | Treatment | Considerations/Other |
Obesity | Refer for nutritional counseling recommend regular exercise. | — |
Developmental delay/ Intellectual disability/ Neurobehavioral issues | See . | Standard treatment (e.g., SSRIs for anxiety or depression, antipsychotics for psychotic disorders, stimulants for ADHD) Sleep disturbance |
Source: GeneReviews — "Xq28 Duplication Syndrome, Int22h1/Int22h2 Mediated"
Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for access to information on clinical studies for a wide range of diseases and conditions. Note: There are no registered, recruiting, or ongoing clinical trials for int22h1/int22h2-mediated Xq28 duplication syndrome to date.
Source: GeneReviews — "Xq28 Duplication Syndrome, Int22h1/Int22h2 Mediated"
View trials for chromosome Xq28 duplication syndrome
Evaluation |
|---|
Frequency |
|---|
Growth | Measure growth/anthropometric parameters. | At each visit Neurodevelopmental milestones cognitive abilities |
evaluations | Conduct thorough assessment screening for anxiety, irritability, aggression, self-injurious behaviors, attention deficits, hyperactivity, impulsivity, sleep disturbances. | At each visit Musculoskeletal |
Hearing | Audiology eval | At least annually in infancy childhood, or more frequently if otherwise clinically indicated |
Vision | Ophthalmology eval | At least annually Family community |
support/resources | Assess family or caregiver need for social work support (e.g., palliative/respite care, home nursing, other local resources), equipment assistive medical devices, /or any other special disability benefits. | At each visit OT = occupational therapist; PT = physical therapist |
Source: GeneReviews — "Xq28 Duplication Syndrome, Int22h1/Int22h2 Mediated"