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familial hypertryptophanemia - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

familial hypertryptophanemia

MONDO:0010907

Also known as:hypertryptophanemiaHYPTRPhypertryptophanemia, familial

Overview

Familial hypertryptophanemia is characterized by intellectual deficit associated with behavioral problems: periodic mood swings, exaggerated affective responses and abnormal sexual behavior. Twelve cases have been reported so far. Congenital abnormalities in tryptophan metabolism appear to be responsible for the tryptophanemia and tryptophanuria.

GeneticsAutosomal recessive · TDO2 (chr 4)

OnsetNEONATAL

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: Increased serum serotonin and Hypertryptophanemia. 21 total HPO annotations.

Organ System	Phenotype Count	Example Features
Brain and nerves	8	Moderate intellectual disability, Amplification of sexual behavior, Stuttering

Genetic Landscape

TDO2 function has not been fully characterized.

Familial hypertryptophanemia has limited evidence linking it to mutations in the TDO2 gene on chromosome 4.

Diagnosis

Genetic testing for TDO2 is available. Testing is considered research-grade for diagnosis.

Prognosis

Phenotype severity distribution: 2 always present features.

Estimated prevalence: <1 in 1,000,000 (VERY_RARE).

Data assembled from 6 of 12 sources · Last updated Sep 18, 2026, 9:11 PM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:600627

Orphanet

European rare disease database

Orphanet:2224

GARD

Genetic and Rare Diseases Info Center

GARD:2871

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?

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familial hypertryptophanemia

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Prognosis

Medical References

External Resources

OMIM

Orphanet

GARD

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Questions for Your Care Team

Questions for Your Care Team

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