raremaprare-disease reference indexOrphadata 2026-06-23 · HPO 2026-09-01
ORPHA:9

Tetrasomy X syndrome

Synonyms: 48,XXXX syndrome · Quadruple X · Tetra X

Type
Malformation syndrome
Group
Disorder
Age of onset
Infancy, Neonatal
Status
active

Tetrasomy X is a sex chromosome anomaly caused by the presence of two extra X chromosomes in females (48,XXXX instead of 46,XX).

1

Names in Orphadata languages

12 of 12 languages
LangNameSynonyms
enTetrasomy X syndrome48,XXXX syndrome · Quadruple X · Tetra X
frSyndrome de tétrasomie xQuadruple X · Syndrome 48,XXXX · Tétra X
deTetrasomie X48,XXXX-Syndrom · Tetra-X-Syndrom
esSíndrome de tetrasomía XSíndrome 48,XXXX · Tetra X · X cuádruple
itSindrome tetrasomia XQuadruplo X · Sindrome 48,XXXX · Tetra X
nlTetrasomie X-syndroom48,XXXX-syndroom · Quadrupel X · Tetra X
ptTetrassomia XSíndrome 48,XXXX
plZespół tetrasomii chromosomu XTetra X · Zespół 48,XXXX
csTetrazomie X48, XXXX syndrom · Quadruple X · Tetra X
ukТетрасомія X48,XXXX синдром · Чотири X · Tetra X
zhX染色体四倍体48,XXXX综合征
trTetrazomi XTetra X · Dörtlü X · 48,XXXX sendromu

Definition in:

2

Cross-references

qualifier = Orphanet mapping relation
SourceCodeQualifierICD relationValidation
ICD-10Q97.1NTBTattributedvalidated
ICD-11LD50.YNTBTindexvalidated
MONDO0019525Evalidated
MeSHC536502Evalidated
UMLSC0265496Evalidated
GARD7754Evalidated

E exact · NTBT this ORPHAcode is narrower than the target · BTNT broader than the target · ND not decided.

3

Classification

Preferential parent (Orphanet linearisation):

Parents in the classifications (5):

No children.

4

Genes

0 direct

Orphanet records no gene directly on this code.

5

Prevalence and incidence

2 records
TypeClassValueAreaQualificationValidationSource
Cases/families50 casesWorldwideCase(s)Validated23494840[PMID]
Point prevalence<1 / 1 000 000—WorldwideClass onlyValidatedORPHANET_23494840[PMID]

Value is Orphadata's ValMoy: the mean estimate per 100 000 for prevalence and incidence, the number of cases or families for case reports.

6

HPO phenotypes

16 annotations · validated 2016-06-01
HPOTerm (as annotated by Orphanet)Diagnostic
Frequent (79-30%)
HP:0000164Abnormality of the dentition
HP:0100543Cognitive impairment
HP:0000286Epicanthus
HP:0001263Global developmental delay
HP:0000316Hypertelorism
HP:0001252Hypotonia
HP:0001382Joint hypermobility
HP:0002974Radioulnar synostosis
HP:0001328Specific learning disability
HP:0000486Strabismus
HP:0000582Upslanted palpebral fissure
Occasional (29-5%)
HP:0030680Abnormal cardiovascular system morphology
HP:0010978Abnormality of immune system physiology
HP:0001156Brachydactyly
HP:0004209Clinodactyly of the 5th finger
HP:0001385Hip dysplasia
7

Sources for this card