Home > D. General pathology > Genetic and developmental anomalies > Chromosomal diseases > Constitutional monosomies > monosomy X
monosomy X
Tuesday 25 January 2005
Epidemiology
1/7000 newborns
increased frequency in abortuses or women with short statute
Synopsis
no pubertal development
50% of cells have chromatin negative Barr bodies
karyotype 45 XO in some or all cells
craniofacial anomalies
- triangular face
- antimongoloid slant of palpebral fissures
- epicanthus
- ptosis
- highly arched palate
- manidbular hypoplasia
- retrognathia
thoracic anomalies
- broad thorax
- shield shaped thorax
- widely spaced nipples
- niple hypoplasia (hypoplastic nipples)
- axillary air absent
aortic anomalies (12640386)
- aortic coarctation
- aortic cystic medial necrosis
- dissecting aneurysms (17042655)
- dissecting thoracic aortic aneurysm (17042655)
- mucopolysaccaride deposition in cardiac valves
- floppy mitral valve
- floppy aortic valve
genitourinary anomalies
- infantile external genitalia
- clitoral hypertrophy
- pubic hair scanty or absent
- female ducts
- female external genitalia
- ovarian dysgenesis
- ovarian agenesis
- streak gonads with fibrous tissue resembling ovarian stroma
- ovaries can be normal in the fetus
- uterine hypoplasia (hypoplastic uterus)
- bifid uterus
- failure of development of secondary sex characters
- renal malformations (11045397)
- horseshoe kidney
- anomalies of renal rotation
- renal agenesis
- renal hypoplasia
- hydronephrosis
- bifid ureters
generalized hypoplasia and partial agenesis of the lymphatic system
- generalized lymphedema
- cystic hygroma
- lymphedema of the dorsum of the feet
skeletal anomalies
- short bi-iliac distance (11920833)
- low inner tibial plate
- slanted downward and inward inner tibial plate with projection beyond metaphysis (Kosowicz sign)
- cubitus valgus
- brachymetacarpia (shortness of fourth and fifth metacarpals)
- raised semilunar carpal bones
cerebrospinal anomalies (central nervous system anomalies)
- slight cortical dysplasia
- gray matter heterotopia
- hydrocephalus
sense organs
- severe myopia
- congenital cataracts
- congenital deafness (17095347)
endocrine anomalies
- low plasmatic estrogens and pregnanediol
- increased FSH
- low urinary 17-ketosteroids
dysimmunity/autoimmunity
- primary biliary cirrhosis
- Hashimoto thyroiditis (autoimmune thyroiditis)
- psoriasis (12602969)
- alopecia areata (12602969)
- cryptogenic cirrhosis (10912494)
In infants
small for gestational age
lymphedema of hands and feet
excess skin on nape of neck (before pterygium colli)
At puberty
small stature
short neck
webbed neck (pterygium colli)
low hair line
ungueal hypoplasia (nail hypoplasia)
hyperconvex nails
keloid scars
Tumor predisposition
gonadal tumors
- gonadal malignancy (if Y chromosomal component present)
- gonadoblastoma (cells with Y or partial Y-chromosome) (15041227)
- Brenner tumor (503400)
- mucinous cystadenoma of borderline malignancy (503400)
halo nevus
atypical polypoid adenomyoma of uterus
endometrial adenocarcinoma
leukemia
soft tissue tumors
neuroblastic tumors (14623457, 11464996)
- adrenal ganglioneuroblastoma
- ganglioneuroma
multiple nevi
retroperitoneal mesenchymoma
thyroid carcinoma
anaplastic pulmonary carcinoma
pituitary eosinophilic adenoma
pituitary chromophobe adenoma
hibernoma
cecal or appendiceal carcinoid tumors
multiple granular cell myoblastomas
medulloblastoma
cerebellar glioma
meningioma
melanoma
endometrial adenocarcinoma
uterine adenoacanthoma
vulvar squamous cell carcinoma
acute myelogenous leukemia
digestive adenocarcinomas
- gastric adenocarcinoma
- colonic adenocarcinoma
Biology
markedly elevated FSH
reduced estrogen levels
atherogenic lipid profile (16705071)
Not associated with gonadal tumors, although case report with mixed germ cell tumor and gonadoblastoma, Archives 1994;118:1135
Micro: streak gonad with fibrous tissue resembling ovarian stroma
Cytogenetics
60% of patients with Turner syndrome in 45,X karyotype
30% of them a Y-sequence
Variants
mosaic monosomy X (mosaic Turner syndrome)
- 46,XY;45,X mosaic
- 46,XX;45,X mosaic
See also
somatic monosomy X (9078298)
- in myelodysplasias (myelodysplastic diseases) (9078298)
References
Sybert VP, McCauley E. Turner’s syndrome. N Engl J Med. 2004 Sep 16;351(12):1227-38. PMID: 15371580
