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Deletion of short arm of chromosome 18

MedGen UID:
96604
Concept ID:
C0432442
Disease or Syndrome
Synonyms: 18p deletion syndrome; 18p minus syndrome; 18p- syndrome; Chromosome 18p deletion syndrome; Del(18p) syndrome; Partial deletion of the short arm of chromosome 18
SNOMED CT: 18p- syndrome (270890001); Deletion of short arm of chromosome 18 (270890001)
Modes of inheritance:
Unknown inheritance
MedGen UID:
989040
Concept ID:
CN307042
Finding
Source: Orphanet
Hereditary clinical entity whose mode of inheritance is unknown.
Not genetically inherited
MedGen UID:
988794
Concept ID:
CN307044
Finding
Source: Orphanet
clinical entity without genetic inheritance.
 
Monarch Initiative: MONDO:0007800
OMIM®: 146390
Orphanet: ORPHA1598

Definition

The main clinical manifestations of chromosome 18p deletion syndrome are mental retardation, growth retardation, craniofacial dysmorphism including round face, dysplastic ears, wide mouth and dental anomalies, and abnormalities of the limbs, genitalia, brain, eyes, and heart. The round face characteristic in the neonatal period and childhood may change to a long face with linear growth of the height of the face (summary by Tsukahara et al., 2001). [from OMIM]

Clinical features

From HPO
Cryptorchidism
MedGen UID:
8192
Concept ID:
C0010417
Congenital Abnormality
Cryptorchidism, or failure of testicular descent, is a common human congenital abnormality with a multifactorial etiology that likely reflects the involvement of endocrine, environmental, and hereditary factors. Cryptorchidism can result in infertility and increases risk for testicular tumors. Testicular descent from abdomen to scrotum occurs in 2 distinct phases: the transabdominal phase and the inguinoscrotal phase (summary by Gorlov et al., 2002).
Gonadal dysgenesis
MedGen UID:
9075
Concept ID:
C0018051
Congenital Abnormality
A congenital disorder characterized by the presence of extremely hypoplastic gonads preventing the development of secondary sex characteristics.
Decreased testicular size
MedGen UID:
66027
Concept ID:
C0241355
Finding
Reduced volume of the testicle (the male gonad).
Micropenis
MedGen UID:
1633603
Concept ID:
C4551492
Congenital Abnormality
Abnormally small penis. At birth, the normal penis is about 3 cm (stretched length from pubic tubercle to tip of penis) with micropenis less than 2.0-2.5 cm.
Toe syndactyly
MedGen UID:
75581
Concept ID:
C0265660
Congenital Abnormality
Webbing or fusion of the toes, involving soft parts only or including bone structure. Bony fusions are referred to as "bony" Syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the toes in a proximo-distal axis are referred to as "Symphalangism".
Radial deviation of finger
MedGen UID:
322852
Concept ID:
C1836189
Finding
Bending or curvature of a finger toward the radial side (i.e., towards the thumb). The deviation is at the metacarpal-phalangeal joint, and this finding is distinct from clinodactyly.
Clinodactyly of the 5th finger
MedGen UID:
340456
Concept ID:
C1850049
Congenital Abnormality
Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger).
Coxa vara
MedGen UID:
1790477
Concept ID:
C5551440
Anatomical Abnormality
Coxa vara includes all forms of decrease of the femoral neck shaft angle (the angle between the neck and the shaft of the femur) to less than 120 degrees.
Small for gestational age
MedGen UID:
65920
Concept ID:
C0235991
Finding
Smaller than normal size according to sex and gestational age related norms, defined as a weight below the 10th percentile for the gestational age.
Short stature
MedGen UID:
87607
Concept ID:
C0349588
Finding
A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).
Macrotia
MedGen UID:
488785
Concept ID:
C0152421
Congenital Abnormality
Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective).
Posteriorly rotated ears
MedGen UID:
96566
Concept ID:
C0431478
Congenital Abnormality
A type of abnormal location of the ears in which the position of the ears is characterized by posterior rotation (the superior part of the ears is rotated towards the back of the head, and the inferior part of the ears towards the front).
Dystonic disorder
MedGen UID:
3940
Concept ID:
C0013421
Sign or Symptom
An abnormally increased muscular tone that causes fixed abnormal postures. There is a slow, intermittent twisting motion that leads to exaggerated turning and posture of the extremities and trunk.
Delayed speech and language development
MedGen UID:
105318
Concept ID:
C0454644
Finding
A degree of language development that is significantly below the norm for a child of a specified age.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Micrognathia
MedGen UID:
44428
Concept ID:
C0025990
Congenital Abnormality
Developmental hypoplasia of the mandible.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Barrel-shaped chest
MedGen UID:
120497
Concept ID:
C0264172
Finding
A rounded, bulging chest that resembles the shape of a barrel. That is, there is an increased anteroposterior diameter and usually some degree of kyphosis.
Round face
MedGen UID:
116087
Concept ID:
C0239479
Finding
The facial appearance is more circular than usual as viewed from the front.
High palate
MedGen UID:
66814
Concept ID:
C0240635
Congenital Abnormality
Height of the palate more than 2 SD above the mean (objective) or palatal height at the level of the first permanent molar more than twice the height of the teeth (subjective).
Short neck
MedGen UID:
99267
Concept ID:
C0521525
Finding
Diminished length of the neck.
Epicanthus
MedGen UID:
151862
Concept ID:
C0678230
Congenital Abnormality
Epicanthus is a condition in which a fold of skin stretches from the upper to the lower eyelid, partially covering the inner canthus. Usher (1935) noted that epicanthus is a normal finding in the fetus of all races. Epicanthus also occurs in association with hereditary ptosis (110100).
Hypomimic face
MedGen UID:
208827
Concept ID:
C0813217
Finding
A reduced degree of motion of the muscles beneath the skin of the face, often associated with reduced facial crease formation.
Anteverted nares
MedGen UID:
326648
Concept ID:
C1840077
Finding
Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).
Redundant neck skin
MedGen UID:
374440
Concept ID:
C1840319
Finding
Excess skin around the neck, often lying in horizontal folds.
Depressed nasal ridge
MedGen UID:
334631
Concept ID:
C1842876
Finding
Lack of prominence of the nose resulting from a posteriorly-placed nasal ridge.
Wide nasal bridge
MedGen UID:
341441
Concept ID:
C1849367
Finding
Increased breadth of the nasal bridge (and with it, the nasal root).
Tooth malposition
MedGen UID:
377692
Concept ID:
C1852504
Finding
Abnormal alignment, positioning, or spacing of the teeth, i.e., misaligned teeth.
Wide intermamillary distance
MedGen UID:
473489
Concept ID:
C1827524
Finding
A larger than usual distance between the left and right nipple.
Ptosis
MedGen UID:
2287
Concept ID:
C0005745
Disease or Syndrome
The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective).
Hypertelorism
MedGen UID:
9373
Concept ID:
C0020534
Finding
Although hypertelorism means an excessive distance between any paired organs (e.g., the nipples), the use of the word has come to be confined to ocular hypertelorism. Hypertelorism occurs as an isolated feature and is also a feature of many syndromes, e.g., Opitz G syndrome (see 300000), Greig cephalopolysyndactyly (175700), and Noonan syndrome (163950) (summary by Cohen et al., 1995).

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVDeletion of short arm of chromosome 18
Follow this link to review classifications for Deletion of short arm of chromosome 18 in Orphanet.

Professional guidelines

PubMed

Feenstra I, Vissers LE, Orsel M, van Kessel AG, Brunner HG, Veltman JA, van Ravenswaaij-Arts CM
Am J Med Genet A 2007 Aug 15;143A(16):1858-67. doi: 10.1002/ajmg.a.31850. PMID: 17632778
Mayall BH, Carrano AV, Golbus MS, Conte FA, Epstein CJ
Clin Genet 1977 Apr;11(4):273-6. doi: 10.1111/j.1399-0004.1977.tb01312.x. PMID: 852145

Recent clinical studies

Diagnosis

Vičić A, Hafner T, Wagner J, Stipoljev F
Coll Antropol 2014 Sep;38(3):1059-62. PMID: 25420396
Kiss P, Osztovics M, Kosztolányi G, Papp A
Acta Paediatr Hung 1984;25(3):263-9. PMID: 6498007

Clinical prediction guides

Vičić A, Hafner T, Wagner J, Stipoljev F
Coll Antropol 2014 Sep;38(3):1059-62. PMID: 25420396
Kiss P, Osztovics M, Kosztolányi G, Papp A
Acta Paediatr Hung 1984;25(3):263-9. PMID: 6498007

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