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Chromosome 16p duplication is a chromosome abnormality that occurs when there is an extra copy of genetic material on the short arm (p) of chromosome 16. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved. Features that often occur in people with chromosome 16p duplication include developmental delay, intellectual disability, behavioral problems and distinctive facial features. Most cases are not inherited, but people can pass the duplication on to their children. Treatment is based on the signs and symptoms present in each person.
No HPO annotations are available for this condition.
Age of onset: at birth.
CTDP1-related congenital cataracts, facial dysmorphism, and neuropathy (CTDP1-CCFDN) is a complex disorder whose major manifestations involve the anterior segment of the eye, the skull and face, the nervous system, and the endocrine system [, , , , , ]. To date, 190 individuals have been identified with a pathogenic variant in CTDP1 [, , , , , , , ]. The following description of the phenotypic features associated with CTDP1-CCFDN is based on these reports. Table 2. CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy: Frequency of Select Features
CTDP1-related congenital cataracts, facial dysmorphism, and neuropathy (CTDP1-CCFDN) should be suspected in individuals with the following clinical findings:
Bilateral congenital cataracts, microcornea, and micropupils
Mildly dysmorphic facial features apparent from late childhood (prominent midface with a well-developed nose, thickening of the perioral tissues, forwardly directed anterior dentition, and micrognathia)
No approved treatments are currently available for partial duplication of the short arm of chromosome 16. The disease remains an area of unmet medical need.
No clinical practice guidelines for CTDP1-related congenital cataracts, facial dysmorphism, and neuropathy (CTDP1-CCFDN) have been published.
To establish the extent of disease and needs in an individual diagnosed with CTDP1-CCFDN and to address the most disabling manifestations, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended.
To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the following evaluations are recommended. Table 6. Recommended Surveillance for Individuals with CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy
No clinical trials have been registered for partial duplication of the short arm of chromosome 16.
3 publications have been identified in PubMed for partial duplication of the short arm of chromosome 16. Research spans Case Report / Case Series (33%), Basic Science / Preclinical (33%), and Epidemiology / Natural History (33%).
Rizea RE (2024). [PMID: 38855489](https://pubmed.ncbi.nlm.nih.gov/38855489/). *Cureus*. [Case Report / Case Series]
Tang D (2024). [PMID: 39716170](https://pubmed.ncbi.nlm.nih.gov/39716170/). *BMC medical genomics*. [Basic Science / Preclinical]
Abgral M (2024). [PMID: 38561025](https://pubmed.ncbi.nlm.nih.gov/38561025/). *Journal of gynecology obstetrics and human reproduction*. [Epidemiology / Natural History]
Data assembled from 4 of 12 sources · Last updated Sep 20, 2026, 3:12 PM UTC
European rare disease database
Genetic and Rare Diseases Info Center
Feature | % of Persons w/Feature | Comment |
|---|---|---|
Ocular manifestations | 100% | Congenital cataracts, microcornea, microphthalmia, micropupils |
Dysmorphic facial features | 100% | Prominent midface w/well-developed nose, thickening of perioral tissues, forwardly directed anterior dentition, micrognathia; more pronounced in affected males in adulthood |
Hypomyelinating peripheral neuropathy | 100% | Symmetric distally accentuated, w/predominantly motor involvement progressing to severe disability by 3rd decade of life |
Developmental delay/Intellectual disability | ~80% | Delayed motor milestones (attributed partly to peripheral neuropathy), delayed early intellectual development, w/most affected children starting to talk at age ~3 yrs |
Cerebellar manifestations | ~20%-40% | Ataxias of stance, gait, nystagmus, intention tremor, dysmetria |
Brain spinal cord MRI abnormalities | 90% | Cerebral atrophy, thin corpus callosum, enlargement of lateral ventricles, focal lesions in subcortical white matter (different in number size), consistent w/demyelination |
Growth deficiency | 90% | Intrauterine growth restriction w/low weight length at birth |
Endocrine manifestations | 50% | Low levels of growth hormone hypogonadotropic hypogonadism Congenital cataracts are the invariable first manifestation of CTDP1-CCFDN . |
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"
Hypo-/demyelinating peripheral neuropathy
Mild nonprogressive intellectual deficit
Intrauterine growth restriction with subsequent small stature and subnormal weight in adulthood
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"
In early infancy, when bilateral congenital cataracts are the only manifestation, the diagnosis of CTDP1-related congenital cataracts, facial dysmorphism, and neuropathy (CTDP1-CCFDN) is made highly probable by the detection of accompanying ophthalmologic abnormalities, such as microcornea and microphthalmia. The differential diagnosis with other conditions presenting in the first year of life with congenital cataracts, microcornea, and microphthalmia is narrowed by the delayed developmental milestones in children with CTDP1-CCFDN and subsequent signs of peripheral neuropathy. CTDP1-CCFDN also shares findings with Marinesco-Sjgren syndrome and GBA2-related Marinesco-Sjgren syndrome-like disorder. See .
Table 3.
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"
Table 4.
Recommended Evaluations Following Initial Diagnosis in Individuals with CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy
System/Concern | Evaluation | Comment
Eyes | Ophthalmologic exam | Assess for cataracts other ocular manifestations.
| Neurologic exam incl measurements of nerve conduction velocity | Assess for peripheral neuropathy cerebellar involvement.
Orthopedics/ physical medicine rehab/ PT OT eval | To incl assessment of:
Gross motor fine motor skills
Mobility, ADL, need for adaptive devices
Need for PT (to improve gross motor skills) /or OT (to improve fine motor skills)
| Developmental assessment |
To incl motor, adaptive, cognitive, speech-language eval
Eval for early intervention/ special education
| Endocrinology eval | Assess growth, fertility issues, osteopenia.
Genetic
counseling | By genetics professionals1 | To inform affected persons their families re nature, MOI, implications of CTDP1-CCFDN to facilitate medical personal decision making
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"
General anesthesia in individuals with CTDP1-CCFDN may cause complications such as pulmonary edema, inspiratory stridor, malignant hyperthermia, and epileptic seizures . Although such complications have not been unequivocally documented, and recommend cautious use of general anesthesia until more information on related risks is available. Prolonged exercise was reported to provoke myalgia in one individual with CTDP1-CCFDN .
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"
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 may not be clinical trials for this disorder.
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"
View trials for partial duplication of the short arm of chromosome 16
System/Concern
Evaluation |
|---|
Frequency |
|---|
Ophthalmologic involvement | Ophthalmology exam | Annually or per treating ophthalmologist(s) |
Neurologic | Neurologic exam | Annually Orthopedics/ physical medicine rehab/ PT OT eval |
Development | Monitor developmental progress educational needs. | At each visit throughout childhood |
Endocrine | Endocrine eval to assess growth, fertility issues, osteopenia | Annually OT = occupational therapy; PT = physical therapy |
Source: GeneReviews — "CTDP1-Related Congenital Cataracts, Facial Dysmorphism, and Neuropathy"