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Microtia-Anotia

MedGen UID:
322201
Concept ID:
C1833486
Disease or Syndrome
Synonym: MICROTIA-ANOTIA
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
Autosomal dominant inheritance
MedGen UID:
141047
Concept ID:
C0443147
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
Not genetically inherited
MedGen UID:
988794
Concept ID:
CN307044
Finding
Source: Orphanet
clinical entity without genetic inheritance.
 
Monarch Initiative: MONDO:0010920
OMIM®: 600674
Orphanet: ORPHA83463

Definition

Microtia-anotia (M-A) can occur either as an isolated defect or in association with other defects. Only in a minority of cases has a genetic or environmental cause been found; in these cases, M-A is usually part of a specific pattern of multiple congenital anomalies. For instance, M-A is an essential component of isotretinoin embryopathy (243440), is an important manifestation of thalidomide embryopathy, and can be part of the prenatal alcohol syndrome and maternal diabetes embryopathy. M-A occurs with a number of single gene disorders, such as Treacher Collins syndrome (154500), branchiootorenal/branchiootic syndromes (see 113650 and 602588), oculoauricular syndrome (612109), microtia with hearing impairment and cleft palate (612290), or chromosomal syndromes, such as trisomy 18. M-A also occurs as part of seemingly nonrandom patterns of multiple defects, such as Goldenhar syndrome (164210) (Mastroiacovo et al., 1995). Alasti and Van Camp (2009) reviewed the genetics of microtia and microtia-associated syndromes and discussed their clinical aspects in relation to the causative genes. They stated that the estimated prevalence of microtia is 0.8 to 4.2 per 10,000 births, that it is more common in males, and that it can have a genetic or environmental predisposition. Reviews Ronde et al. (2023) reviewed the international classification and clinical management strategies for craniofacial microsomia and microtia (CFM; see 164210), and tabulated survey responses from 57 professionals involved in management of CFM patients. The authors noted that although the International Consortium for Health Outcomes Measurement (ICHOM) criteria for CFM exclude isolated microtia from the phenotypic spectrum of CFM, the question of whether isolated microtia can be considered the mildest form of CFM is debated in the literature. No consensus was reached in their survey, as a majority of respondents agreed with the ICHOM criteria but also considered isolated microtia to be a mild form of CFM. [from OMIM]

Clinical features

From HPO
Microtia
MedGen UID:
57535
Concept ID:
C0152423
Congenital Abnormality
Underdevelopment of the external ear.
Anotia
MedGen UID:
152377
Concept ID:
C0702139
Congenital Abnormality
Complete absence of any auricular structures.
Holoprosencephaly sequence
MedGen UID:
38214
Concept ID:
C0079541
Congenital Abnormality
Nonsyndromic holoprosencephaly is an abnormality of brain development that also affects the head and face. Normally, the brain divides into two halves (hemispheres) during early development. Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The severity of nonsyndromic holoprosencephaly varies widely among affected individuals, even within the same family.\n\nNonsyndromic holoprosencephaly can be grouped into four types according to the degree of brain division. From most to least severe, the types are known as alobar, semi-lobar, lobar, and middle interhemispheric variant (MIHV). In the most severe forms of nonsyndromic holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe nonsyndromic holoprosencephaly die before birth or soon after. In the less severe forms, the brain is partially divided and the eyes are usually set close together (hypotelorism). The life expectancy of these affected individuals varies depending on the severity of symptoms.\n\nPeople with nonsyndromic holoprosencephaly often have a small head (microcephaly), although they can develop a buildup of fluid in the brain (hydrocephalus) that causes increased head size (macrocephaly). Other features may include an opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip), one central front tooth instead of two (a single maxillary central incisor), and a flat nasal bridge. The eyeballs may be abnormally small (microphthalmia) or absent (anophthalmia).\n\nSome individuals with nonsyndromic holoprosencephaly have a distinctive pattern of facial features, including a narrowing of the head at the temples, outside corners of the eyes that point upward (upslanting palpebral fissures), large ears, a short nose with upturned nostrils, and a broad and deep space between the nose and mouth (philtrum). In general, the severity of facial features is directly related to the severity of the brain abnormalities. However, individuals with mildly affected facial features can have severe brain abnormalities. Some people do not have apparent structural brain abnormalities but have some of the facial features associated with this condition. These individuals are considered to have a form of the disorder known as microform holoprosencephaly and are typically identified after the birth of a severely affected family member.\n\nMost people with nonsyndromic holoprosencephaly have developmental delay and intellectual disability. Affected individuals also frequently have a malfunctioning pituitary gland, which is a gland located at the base of the brain that produces several hormones. Because pituitary dysfunction leads to the partial or complete absence of these hormones, it can cause a variety of disorders. Most commonly, people with nonsyndromic holoprosencephaly and pituitary dysfunction develop diabetes insipidus, a condition that disrupts the balance between fluid intake and urine excretion. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature, heart rate, and breathing. The sense of smell may be diminished (hyposmia) or completely absent (anosmia) if the part of the brain that processes smells is underdeveloped or missing.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVMicrotia-Anotia
Follow this link to review classifications for Microtia-Anotia in Orphanet.

Recent clinical studies

Etiology

Ryan MA, Olshan AF, Canfield MA, Hoyt AT, Scheuerle AE, Carmichael SL, Shaw GM, Werler MM, Fisher SC, Desrosiers TA; National Birth Defects Prevention Study
Int J Pediatr Otorhinolaryngol 2019 Jul;122:18-26. Epub 2019 Mar 23 doi: 10.1016/j.ijporl.2019.03.026. PMID: 30928866Free PMC Article
Shibazaki-Yorozuya R, Nagata S
J Craniofac Surg 2019 Jan;30(1):66-70. doi: 10.1097/SCS.0000000000004915. PMID: 30616309
Hoyt AT, Canfield MA, Shaw GM, Waller DK, Polen KN, Ramadhani T, Anderka MT, Scheuerle AE; National Birth Defects Prevention Study
Birth Defects Res A Clin Mol Teratol 2014 Nov;100(11):852-62. Epub 2014 Jul 30 doi: 10.1002/bdra.23282. PMID: 25074828Free PMC Article
Luquetti DV, Leoncini E, Mastroiacovo P
Birth Defects Res A Clin Mol Teratol 2011 Sep;91(9):813-22. Epub 2011 Jun 7 doi: 10.1002/bdra.20836. PMID: 21656661Free PMC Article
Forrester MB, Merz RD
Congenit Anom (Kyoto) 2005 Dec;45(4):119-24. doi: 10.1111/j.1741-4520.2005.00080.x. PMID: 16359491

Diagnosis

Cheng YF, Xirasagar S, Liu TC, Kuo NW, Lin HC
Eur Arch Otorhinolaryngol 2021 Nov;278(11):4315-4319. Epub 2021 Jul 26 doi: 10.1007/s00405-021-07014-x. PMID: 34309752
Shibazaki-Yorozuya R, Nagata S
J Craniofac Surg 2019 Jan;30(1):66-70. doi: 10.1097/SCS.0000000000004915. PMID: 30616309
Rai B, Gouda R, Moka S, Dunbar LE
J Child Neurol 2015 Jul;30(8):1086-8. Epub 2014 Sep 16 doi: 10.1177/0883073814544367. PMID: 25227517
Paput L, Bánhidy F, Czeizel AE
Int J Pediatr Otorhinolaryngol 2011 May;75(5):639-47. Epub 2011 Feb 26 doi: 10.1016/j.ijporl.2011.01.041. PMID: 21354632
Wang RY, Earl DL, Ruder RO, Graham JM Jr
Pediatrics 2001 Aug;108(2):E32. doi: 10.1542/peds.108.2.e32. PMID: 11483842

Therapy

Joukhadar N, McKee D, Caouette-Laberge L, Bezuhly M
Plast Reconstr Surg 2020 Aug;146(2):205e-216e. doi: 10.1097/PRS.0000000000006997. PMID: 32740598
Ryan MA, Olshan AF, Canfield MA, Hoyt AT, Scheuerle AE, Carmichael SL, Shaw GM, Werler MM, Fisher SC, Desrosiers TA; National Birth Defects Prevention Study
Int J Pediatr Otorhinolaryngol 2019 Jul;122:18-26. Epub 2019 Mar 23 doi: 10.1016/j.ijporl.2019.03.026. PMID: 30928866Free PMC Article
Hoyt AT, Canfield MA, Shaw GM, Waller DK, Polen KN, Ramadhani T, Anderka MT, Scheuerle AE; National Birth Defects Prevention Study
Birth Defects Res A Clin Mol Teratol 2014 Nov;100(11):852-62. Epub 2014 Jul 30 doi: 10.1002/bdra.23282. PMID: 25074828Free PMC Article
Paput L, Bánhidy F, Czeizel AE
Int J Pediatr Otorhinolaryngol 2011 May;75(5):639-47. Epub 2011 Feb 26 doi: 10.1016/j.ijporl.2011.01.041. PMID: 21354632
Lammer EJ, Chen DT, Hoar RM, Agnish ND, Benke PJ, Braun JT, Curry CJ, Fernhoff PM, Grix AW Jr, Lott IT
N Engl J Med 1985 Oct 3;313(14):837-41. doi: 10.1056/NEJM198510033131401. PMID: 3162101

Prognosis

Cheng YF, Xirasagar S, Liu TC, Kuo NW, Lin HC
Eur Arch Otorhinolaryngol 2021 Nov;278(11):4315-4319. Epub 2021 Jul 26 doi: 10.1007/s00405-021-07014-x. PMID: 34309752
Joukhadar N, McKee D, Caouette-Laberge L, Bezuhly M
Plast Reconstr Surg 2020 Aug;146(2):205e-216e. doi: 10.1097/PRS.0000000000006997. PMID: 32740598
Vinikoor-Imler LC, Davis JA, Meyer RE, Luben TJ
Birth Defects Res A Clin Mol Teratol 2013 Oct;97(10):696-701. Epub 2013 Jul 29 doi: 10.1002/bdra.23159. PMID: 23897551
Paput L, Bánhidy F, Czeizel AE
Int J Pediatr Otorhinolaryngol 2011 May;75(5):639-47. Epub 2011 Feb 26 doi: 10.1016/j.ijporl.2011.01.041. PMID: 21354632
Giannatou E, Leze H, Katana A, Kolialexi A, Mavrou A, Kanavakis E, Kitsiou-Tzeli S
Genet Couns 2009;20(2):181-7. PMID: 19650416

Clinical prediction guides

Lu M, Lu X, Jiang H, Pan B
J Craniofac Surg 2020 Mar/Apr;31(2):538-541. doi: 10.1097/SCS.0000000000006244. PMID: 31977690
Ryan MA, Olshan AF, Canfield MA, Hoyt AT, Scheuerle AE, Carmichael SL, Shaw GM, Werler MM, Fisher SC, Desrosiers TA; National Birth Defects Prevention Study
Int J Pediatr Otorhinolaryngol 2019 Jul;122:18-26. Epub 2019 Mar 23 doi: 10.1016/j.ijporl.2019.03.026. PMID: 30928866Free PMC Article
Shibazaki-Yorozuya R, Nagata S
J Craniofac Surg 2019 Jan;30(1):66-70. doi: 10.1097/SCS.0000000000004915. PMID: 30616309
Hoyt AT, Canfield MA, Shaw GM, Waller DK, Polen KN, Ramadhani T, Anderka MT, Scheuerle AE; National Birth Defects Prevention Study
Birth Defects Res A Clin Mol Teratol 2014 Nov;100(11):852-62. Epub 2014 Jul 30 doi: 10.1002/bdra.23282. PMID: 25074828Free PMC Article
Luquetti DV, Leoncini E, Mastroiacovo P
Birth Defects Res A Clin Mol Teratol 2011 Sep;91(9):813-22. Epub 2011 Jun 7 doi: 10.1002/bdra.20836. PMID: 21656661Free PMC Article

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