How is Kaya-Barakat-Masson syndrome inherited?

Kaya-Barakat-Masson syndrome follows an autosomal recessive inheritance pattern. This means a child must inherit a copy of the altered gene from both parents to develop the condition. Parents who each carry one copy typically do not show symptoms.

How rare is Kaya-Barakat-Masson syndrome?

Kaya-Barakat-Masson syndrome is classified as very rare. The estimated prevalence is approximately <1 in 1,000,000. Because rare disease data can be limited, actual numbers may differ from published estimates.

How is Kaya-Barakat-Masson syndrome diagnosed?

Information about diagnosis is currently limited for this condition.

Are there treatments for Kaya-Barakat-Masson syndrome?

Information about treatment is currently limited for this condition.

What complications might arise from Kaya-Barakat-Masson syndrome?

Currently, there is limited information about the specific complications that may arise from Kaya-Barakat-Masson syndrome. Because this condition is rare, many aspects of its clinical presentation and potential complications are not well understood. Ongoing research may help identify these complications in the future.

How does Kaya-Barakat-Masson syndrome affect daily life?

Information about how Kaya-Barakat-Masson syndrome affects daily life is currently limited. Since the condition is rare, its impact on daily activities and quality of life is not fully known. Families may need to adapt their routines based on the symptoms and challenges that arise.

What is the prognosis for someone with Kaya-Barakat-Masson syndrome?

The prognosis for Kaya-Barakat-Masson syndrome is not clearly defined due to limited information about the condition. Since it is a rare genetic disorder, researchers are still working to understand its long-term effects and outcomes. Families may need to stay informed as new research emerges.

Are there specialists who can help manage Kaya-Barakat-Masson syndrome?

Currently, there is limited information about specific specialists for Kaya-Barakat-Masson syndrome. However, families may benefit from consulting with geneticists or specialists in rare diseases. These professionals can help provide support and guidance as more information about the condition becomes available.

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Kaya-Barakat-Masson syndrome - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

Kaya-Barakat-Masson syndrome

MONDO:0030878

Also known as:KABAMAS

Overview

GeneticsAutosomal recessive · YIF1B (chr 19)

OnsetANTENATAL

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

Features include always present findings: Delayed speech and language development, Global developmental delay, Generalized hypotonia, and Dyskinesia and others; and very common findings: Delayed ability to roll over, Microcephaly, and Limb dystonia. 20 total HPO annotations.

Organ System	Phenotype Count	Example Features
Brain and nerves	10	Spastic tetraplegia, Brain shrinkage (cerebral atrophy), Delayed speech and language development

Genetic Landscape

Assembled from HGNC gene records, ClinGen gene-disease validity evidence, and ClinVar pathogenic variant data. Validity classifications reflect the strength of published evidence linking each gene to this disease.

YIF1B function has not been fully characterized.

Kaya-Barakat-Masson syndrome is caused by mutations in the YIF1B gene on chromosome 19.

GeneReviews

Clinical Guidance

Although the number of reported individuals with YIF1B-NDD is small (n=25) and the overall phenotype of this disorder is profound to severe, the phenotype of individuals with biallelic protein-truncating YIF1B variants tends to be more severe compared to that of individuals with biallelic missense variants . Limited developmental milestones – including limited speech development (4/24), head control (5/24), and capacity to sit (4/24), stand (2/24), and walk (2/24) – were only observed in individuals with biallelic missense variants. This might be due to residual activity of YIF1B in those with missense variants compared to protein-truncating variants .

Diagnosis

Drawn from GeneReviews diagnostic guidelines, newborn screening panel status (RUSP), and ClinGen gene-disease validity classifications. Reflects current clinical evidence and consensus where available.

GeneReviews

Diagnostic Criteria

Suggestive Findings

YIF1B-related neurodevelopmental disorder (YIF1B-NDD) should be considered in probands with the following clinical, imaging, and family history findings.

Clinical findings

Source: GeneReviews — "YIF1B-Related Neurodevelopmental Disorder"

Treatment

Compiled from FDA-approved drug records, orphan drug designations, and FDA Adverse Event Reporting System (FAERS) safety data. GeneReviews management guidance is included where available.

No approved treatments are currently available for Kaya-Barakat-Masson syndrome. The disease remains an area of unmet medical need.

GeneReviews

Management Guidelines

No clinical practice guidelines for YIF1B-related neurodevelopmental disorder (YIF1B-NDD) have been published. In the absence of published guidelines, the following recommendations are based on the authors' personal experience managing individuals with this disorder. Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with YIF1B-NDD, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 3. YIF1B-Related Neurodevelopmental Disorder: Recommended Evaluations Following Initial Diagnosis

Prognosis

Based on GeneReviews surveillance recommendations, HPO phenotype frequency and severity annotations, and published prevalence estimates from Orphanet and OMIM.

GeneReviews

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 5. YIF1B-Related Neurodevelopmental Disorder: Recommended Surveillance

Data assembled from 7 of 12 sources · Last updated Sep 20, 2026, 1:59 AM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:619125

Orphanet

European rare disease database

Orphanet:684240

GARD

Genetic and Rare Diseases Info Center

GARD:18537

Questions for Your Care Team

→Should my partner and I meet with a genetic counselor to discuss carrier status and family planning?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

FAQ

Frequently Asked Questions

Common questions about Kaya-Barakat-Masson syndrome

Kaya-Barakat-Masson syndrome, also known as KABAMAS, is a rare genetic condition recorded in several genetic and rare disease databases. It is associated with the OMIM entry 619125, Orphanet entry 684240, and GARD entry 18537. This condition has been linked to changes in the YIF1B gene, although detailed information about the condition is currently limited. Because of the rarity of the condition, many aspects such as its full clinical presentation, progression, and overall impact on quality of life remain unclear. Further research is needed to better understand Kaya-Barakat-Masson syndrome and provide more detailed information on its management and outcomes.

Information about symptoms is currently limited for this condition.

Kaya-Barakat-Masson syndrome has been linked to changes in the YIF1B gene. However, detailed information about the underlying causes, genetic variations, and risk factors remains limited. Associated genes include YIF1B.

← Back to All Diseases

GeneReviews

Clinical Guidance

YIF1B-related neurodevelopmental disorder (YIF1B-NDD) is characterized by severe-to-profound developmental delay/ intellectual disability with variable motor abnormalities including axial hypotonia, peripheral hypertonia, dystonia, and dyskinesia; absence of speech in most individuals or very limited speech subject to regression; feeding difficulties; seizures; postnatal microcephaly with nonspecific brain MRI abnormalities; and ophthalmologic involvement (strabismus, nystagmus, optic atrophy, and cortical blindness). Some individuals have hypoventilation. To date, 25 individuals have been identified with biallelic pathogenic variants in YIF1B [, , , ]. The following description of the phenotypic features associated with this condition is based on these reports. Table 2. YIF1B-Related Neurodevelopmental Disorder: Frequency of Select Features

Feature	Proportion of Persons w/Feature1	Comment
Developmental delay	24/24	Severe to profound
Generalized hypotonia of infancy	20/24	—
Intellectual disability	24/24	Severe to profound
Peripheral spasticity hyperreflexia	22/23	—
Infant feeding difficulties	20/24	—
Dystonia	12/24	—
Dyskinesia or tremor	9/21	—
Epilepsy	15/23	Myoclonic, generalized tonic-clonic, infantile spasms
Microcephaly	16/24	Postnatal onset is most common.
Strabismus	11/19	—
Nystagmus	5/20	—
Optic atrophy	2/21	—
Central hypoventilation	6/19	When brain stem is affected
Premature death	5/25	Death occurred before age 2 yrs in 5 persons. Based on , , , 1. Developmental delay. All individuals with YIF1B-NDD presented with severe-to-profound developmental delay, evident in the first month of life [, , , ]. Normal developmental milestones were most often not achieved.

Source: GeneReviews — "YIF1B-Related Neurodevelopmental Disorder"

System/Concern	Evaluation	Comment
Development	Developmental assessment	To incl motor, adaptive, cognitive, speech-language eval; Eval for early intervention/ special education Gastrointestinal/ Feeding
Neurologic	Neurologic eval	Assess for movement disorder signs of hypoventilation.; Assess muscle tone.; Consider EEG if seizures are a concern.; Consider brain MRI if not performed previously.
Eyes	Ophthalmologic eval	To assess for reduced vision, abnormal ocular movement, best corrected visual acuity, refractive errors, strabismus, more complex findings (e.g., cortical blindness) that may require referral for subspecialty care /or low vision services Neurobehavioral/
Psychiatric	Neuropsychiatric eval	For persons age 12 mos: screening for concerns incl findings suggestive of ASD, anxiety, /or aggression
Genetic counseling	By genetics professionals1	To obtain a pedigree inform affected persons their families re nature, MOI, implications of YIF1B-NDD to facilitate medical personal decision making Family support
resources	By clinicians, wider care team, family support organizations	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; YIF1B-NDD = YIF1B-related neurodevelopmental disorder 1.
YIF1B-Related Neurodevelopmental Disorder: Treatment of Manifestations Manifestation/Concern	Treatment	Considerations/Other Developmental delay/ Intellectual disability/
Neurobehavioral issues	See .	Feeding issues/ Poor weight gain
Movement disorder	Consider standardized treatments for movement disorders by experienced neurologist.	Individual case reports indicate that levodopa or carbidopa did not improve movement disorders, while partial improvement was obtained using trihexyphenidyl.1 However, there is no substantial evidence for the efficacy of this treatment in this disorder.
Epilepsy	Standardized treatment w/ASM by experienced neurologist	Many ASMs may be effective; none has been demonstrated effective specifically for this disorder.; Education of parents/caregivers2
Eyes	Treatment per ophthalmologist	For refractive errors, strabismus Low vision services
Central hypoventilation	Consider ventilation therapy if hypoventilation becomes evident.	Consider referral to ventilation specialist. Family/Community

Kisho

Kaya-Barakat-Masson syndrome

Overview

Clinical Presentation

Genetic Landscape

Clinical Guidance

Diagnosis

Diagnostic Criteria

Suggestive Findings

Treatment

Management Guidelines

Prognosis

Surveillance Guidelines

Medical References

External Resources

OMIM

Orphanet

GARD

Questions for Your Care Team

Questions for Your Care Team

FAQ

Frequently Asked Questions

Clinical Guidance

Explore clinical features

Differential Diagnosis

Therapies Under Investigation

Clinical Trials

Kaya-Barakat-Masson syndrome

Overview

Clinical Presentation

Genetic Landscape

Clinical Guidance

Diagnosis

Diagnostic Criteria

Suggestive Findings

Treatment

Management Guidelines

Prognosis

Surveillance Guidelines

Medical References

External Resources

OMIM

Orphanet

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team

FAQ

Frequently Asked Questions

What is Kaya-Barakat-Masson syndrome?

What are the symptoms of Kaya-Barakat-Masson syndrome?

What causes Kaya-Barakat-Masson syndrome?

How is Kaya-Barakat-Masson syndrome inherited?

How rare is Kaya-Barakat-Masson syndrome?

How is Kaya-Barakat-Masson syndrome diagnosed?

Are there treatments for Kaya-Barakat-Masson syndrome?

What complications might arise from Kaya-Barakat-Masson syndrome?

How does Kaya-Barakat-Masson syndrome affect daily life?

What is the prognosis for someone with Kaya-Barakat-Masson syndrome?

Are there specialists who can help manage Kaya-Barakat-Masson syndrome?

Clinical Guidance

Explore clinical features

Differential Diagnosis

Therapies Under Investigation

Clinical Trials