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Warburg micro syndrome 2(WARBM2)

MedGen UID:
481844
Concept ID:
C3280214
Disease or Syndrome
Synonyms: MICRO SYNDROME 2; WARBM2
 
Gene (location): RAB3GAP2 (1q41)
 
Monarch Initiative: MONDO:0013641
OMIM®: 614225

Disease characteristics

Excerpted from the GeneReview: RAB18 Deficiency
RAB18 deficiency is the molecular deficit underlying both Warburg micro syndrome (characterized by eye, nervous system, and endocrine abnormalities) and Martsolf syndrome (characterized by similar – but milder – findings). To date Warburg micro syndrome comprises >96% of reported individuals with genetically defined RAB18 deficiency. The hallmark ophthalmologic findings are bilateral congenital cataracts, usually accompanied by microphthalmia, microcornea (diameter <10), and small atonic pupils. Poor vision despite early cataract surgery likely results from progressive optic atrophy and cortical visual impairment. Individuals with Warburg micro syndrome have severe to profound intellectual disability (ID); those with Martsolf syndrome have mild to moderate ID. Some individuals with RAB18 deficiency also have epilepsy. In Warburg micro syndrome, a progressive ascending spastic paraplegia typically begins with spastic diplegia and contractures during the first year, followed by upper-limb involvement leading to spastic quadriplegia after about age five years, often eventually causing breathing difficulties. In Martsolf syndrome infantile hypotonia is followed primarily by slowly progressive lower-limb spasticity. Hypogonadism – when present – manifests in both syndromes, in males as micropenis and/or cryptorchidism and in females as hypoplastic labia minora, clitoral hypoplasia, and small introitus. [from GeneReviews]
Authors:
Mark Handley  |  Eamonn Sheridan   view full author information

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).
Small scrotum
MedGen UID:
141577
Concept ID:
C0455792
Finding
Apparently small scrotum for age.
Hypoplastic labia majora
MedGen UID:
107566
Concept ID:
C0566899
Finding
Undergrowth of the outer labia.
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.
Overlapping toe
MedGen UID:
182531
Concept ID:
C0920299
Anatomical Abnormality
Describes a foot digit resting on the dorsal surface of an adjacent digit when the foot is at rest. Initially clawing may be dynamic and only noticeable on walking. Over time the plantar plate tears, subluxation occurs at the metatarsophalangeal joint (MTPJ), and the deformity becomes permanent.
Clinodactyly of the 4th toe
MedGen UID:
866488
Concept ID:
C4020740
Finding
Bending or curvature of a fourth toe in the tibial direction (i.e., towards the big toe).
Clinodactyly of the 5th toe
MedGen UID:
871256
Concept ID:
C4025741
Anatomical Abnormality
Bending or curvature of a fifth toe in the tibial direction (i.e., towards the big toe).
Postnatal growth retardation
MedGen UID:
395343
Concept ID:
C1859778
Finding
Slow or limited growth after birth.
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).
Asymmetry of the ears
MedGen UID:
257908
Concept ID:
C1168239
Finding
An asymmetriy, i.e., difference in size, shape or position between the left and right ear.
Spastic diplegia
MedGen UID:
44181
Concept ID:
C0023882
Disease or Syndrome
Spasticity (neuromuscular hypertonia) primarily in the muscles of the legs, hips, and pelvis.
Intellectual disability, severe
MedGen UID:
48638
Concept ID:
C0036857
Mental or Behavioral Dysfunction
Severe mental retardation is defined as an intelligence quotient (IQ) in the range of 20-34.
Global brain atrophy
MedGen UID:
66840
Concept ID:
C0241816
Pathologic Function
Unlocalized atrophy of the brain with decreased total brain matter volume and increased ventricular size.
Polymicrogyria
MedGen UID:
78605
Concept ID:
C0266464
Congenital Abnormality
Polymicrogyria is a congenital malformation of the cerebral cortex characterized by abnormal cortical layering (lamination) and an excessive number of small gyri (folds).
Hypoplasia of the corpus callosum
MedGen UID:
138005
Concept ID:
C0344482
Congenital Abnormality
Underdevelopment of the corpus callosum.
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.
Severe global developmental delay
MedGen UID:
332436
Concept ID:
C1837397
Finding
A severe delay in the achievement of motor or mental milestones in the domains of development of a child.
Undetectable visual evoked potentials
MedGen UID:
376697
Concept ID:
C1850069
Finding
Absent speech
MedGen UID:
340737
Concept ID:
C1854882
Finding
Complete lack of development of speech and language abilities.
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.
Brachycephaly
MedGen UID:
113165
Concept ID:
C0221356
Congenital Abnormality
An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width.
Flexion contracture
MedGen UID:
83069
Concept ID:
C0333068
Anatomical Abnormality
A flexion contracture is a bent (flexed) joint that cannot be straightened actively or passively. It is thus a chronic loss of joint motion due to structural changes in muscle, tendons, ligaments, or skin that prevents normal movement of joints.
Secondary microcephaly
MedGen UID:
608952
Concept ID:
C0431352
Finding
Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth.
Axial hypotonia
MedGen UID:
342959
Concept ID:
C1853743
Finding
Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Low anterior hairline
MedGen UID:
331280
Concept ID:
C1842366
Finding
Distance between the hairline (trichion) and the glabella (the most prominent point on the frontal bone above the root of the nose), in the midline, more than two SD below the mean. Alternatively, an apparently decreased distance between the hairline and the glabella.
Prominent nasal bridge
MedGen UID:
343051
Concept ID:
C1854113
Finding
Anterior positioning of the nasal root in comparison to the usual positioning for age.
Short nose
MedGen UID:
343052
Concept ID:
C1854114
Finding
Distance from nasion to subnasale more than two standard deviations below the mean, or alternatively, an apparently decreased length from the nasal root to the nasal tip.
Developmental cataract
MedGen UID:
3202
Concept ID:
C0009691
Congenital Abnormality
A cataract that occurs congenitally as the result of a developmental defect, in contrast to the majority of cataracts that occur in adulthood as the result of degenerative changes of the lens.
Microphthalmia
MedGen UID:
10033
Concept ID:
C0026010
Congenital Abnormality
Microphthalmia is an eye abnormality that arises before birth. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmia may or may not result in significant vision loss.\n\nPeople with microphthalmia may also have a condition called coloboma. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in the colored part of the eye called the iris; the retina, which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or in the optic nerves, which carry information from the eyes to the brain. Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision.\n\nPeople with microphthalmia may also have other eye abnormalities, including clouding of the lens of the eye (cataract) and a narrowed opening of the eye (narrowed palpebral fissure). Additionally, affected individuals may have an abnormality called microcornea, in which the clear front covering of the eye (cornea) is small and abnormally curved.\n\nBetween one-third and one-half of affected individuals have microphthalmia as part of a syndrome that affects other organs and tissues in the body. These forms of the condition are described as syndromic. When microphthalmia occurs by itself, it is described as nonsyndromic or isolated.
Optic atrophy
MedGen UID:
18180
Concept ID:
C0029124
Disease or Syndrome
Atrophy of the optic nerve. Optic atrophy results from the death of the retinal ganglion cell axons that comprise the optic nerve and manifesting as a pale optic nerve on fundoscopy.
Cataract
MedGen UID:
39462
Concept ID:
C0086543
Disease or Syndrome
A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.
Microcornea
MedGen UID:
78610
Concept ID:
C0266544
Congenital Abnormality
A congenital abnormality of the cornea in which the cornea and the anterior segment of the eye are smaller than normal. The horizontal diameter of the cornea does not reach 10 mm even in adulthood.
Deeply set eye
MedGen UID:
473112
Concept ID:
C0423224
Finding
An eye that is more deeply recessed into the plane of the face than is typical.

Recent clinical studies

Prognosis

Deneubourg C, Ramm M, Smith LJ, Baron O, Singh K, Byrne SC, Duchen MR, Gautel M, Eskelinen EL, Fanto M, Jungbluth H
Autophagy 2022 Mar;18(3):496-517. Epub 2021 Aug 19 doi: 10.1080/15548627.2021.1943177. PMID: 34130600Free PMC Article
Zhou D, Wang Q, Liu H
Medicine (Baltimore) 2021 Jan 15;100(2):e22902. doi: 10.1097/MD.0000000000022902. PMID: 33466118Free PMC Article
Asahina M, Endoh Y, Matsubayashi T, Fukuda T, Ogata T
Brain Dev 2016 Mar;38(3):337-40. Epub 2015 Oct 1 doi: 10.1016/j.braindev.2015.09.006. PMID: 26421802
Bem D, Yoshimura S, Nunes-Bastos R, Bond FC, Kurian MA, Rahman F, Handley MT, Hadzhiev Y, Masood I, Straatman-Iwanowska AA, Cullinane AR, McNeill A, Pasha SS, Kirby GA, Foster K, Ahmed Z, Morton JE, Williams D, Graham JM, Dobyns WB, Burglen L, Ainsworth JR, Gissen P, Müller F, Maher ER, Barr FA, Aligianis IA
Am J Hum Genet 2011 Apr 8;88(4):499-507. doi: 10.1016/j.ajhg.2011.03.012. PMID: 21473985Free PMC Article
Morris-Rosendahl DJ, Segel R, Born AP, Conrad C, Loeys B, Brooks SS, Müller L, Zeschnigk C, Botti C, Rabinowitz R, Uyanik G, Crocq MA, Kraus U, Degen I, Faes F
Eur J Hum Genet 2010 Oct;18(10):1100-6. Epub 2010 May 26 doi: 10.1038/ejhg.2010.79. PMID: 20512159Free PMC Article

Clinical prediction guides

Asahina M, Endoh Y, Matsubayashi T, Fukuda T, Ogata T
Brain Dev 2016 Mar;38(3):337-40. Epub 2015 Oct 1 doi: 10.1016/j.braindev.2015.09.006. PMID: 26421802
Wiedmer M, Oevermann A, Borer-Germann SE, Gorgas D, Shelton GD, Drögemüller M, Jagannathan V, Henke D, Leeb T
G3 (Bethesda) 2015 Nov 23;6(2):255-62. doi: 10.1534/g3.115.022707. PMID: 26596647Free PMC Article
Arroyo-Carrera I, de Zaldívar Tristancho MS, Bermejo-Sánchez E, Martínez-Fernández ML, López-Lafuente A, MacDonald A, Zúñiga Á, Luis Gómez-Skarmeta J, Luisa Martínez-Frías M
Am J Med Genet A 2015 Jun;167(6):1243-51. Epub 2015 Apr 21 doi: 10.1002/ajmg.a.36878. PMID: 25899426
Bem D, Yoshimura S, Nunes-Bastos R, Bond FC, Kurian MA, Rahman F, Handley MT, Hadzhiev Y, Masood I, Straatman-Iwanowska AA, Cullinane AR, McNeill A, Pasha SS, Kirby GA, Foster K, Ahmed Z, Morton JE, Williams D, Graham JM, Dobyns WB, Burglen L, Ainsworth JR, Gissen P, Müller F, Maher ER, Barr FA, Aligianis IA
Am J Hum Genet 2011 Apr 8;88(4):499-507. doi: 10.1016/j.ajhg.2011.03.012. PMID: 21473985Free PMC Article
Morris-Rosendahl DJ, Segel R, Born AP, Conrad C, Loeys B, Brooks SS, Müller L, Zeschnigk C, Botti C, Rabinowitz R, Uyanik G, Crocq MA, Kraus U, Degen I, Faes F
Eur J Hum Genet 2010 Oct;18(10):1100-6. Epub 2010 May 26 doi: 10.1038/ejhg.2010.79. PMID: 20512159Free PMC Article

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