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Intellectual developmental disorder, autosomal dominant 68(MRD68)

MedGen UID:
1802176
Concept ID:
C5677008
Mental or Behavioral Dysfunction
Synonyms: MENTAL RETARDATION, AUTOSOMAL DOMINANT 68; MRD68
 
Gene (location): KMT2B (19q13.12)
 
Monarch Initiative: MONDO:0030969
OMIM®: 619934

Definition

Autosomal dominant intellectual developmental disorder-68 (MRD68) is characterized by developmental delay/intellectual disability, microcephaly, poor growth, feeding difficulties, and dysmorphic features. Some patients may have autism spectrum disorder or attention deficit-hyperactivity disorder (ADHD) (Cif et al., 2020). [from OMIM]

Clinical features

From HPO
Urinary incontinence
MedGen UID:
22579
Concept ID:
C0042024
Finding
Loss of the ability to control the urinary bladder leading to involuntary urination.
Narrow palm
MedGen UID:
346628
Concept ID:
C1857632
Finding
For children from birth to 4 years of age, the palm width is more than 2 SD below the mean; for children from 4 to 16 years of age the palm width is below the 5th centile; or, the width of the palm appears disproportionately narrow for its length.
Broad hallux
MedGen UID:
401165
Concept ID:
C1867131
Finding
Visible increase in width of the hallux without an increase in the dorso-ventral dimension.
2-3 toe syndactyly
MedGen UID:
1645640
Concept ID:
C4551570
Congenital Abnormality
Syndactyly with fusion of toes two and three.
Patent ductus arteriosus
MedGen UID:
4415
Concept ID:
C0013274
Congenital Abnormality
In utero, the ductus arteriosus (DA) serves to divert ventricular output away from the lungs and toward the placenta by connecting the main pulmonary artery to the descending aorta. A patent ductus arteriosus (PDA) in the first 3 days of life is a physiologic shunt in healthy term and preterm newborn infants, and normally is substantially closed within about 24 hours after bith and completely closed after about three weeks. Failure of physiologcal closure is referred to a persistent or patent ductus arteriosus (PDA). Depending on the degree of left-to-right shunting, PDA can have clinical consequences.
Fetal growth restriction
MedGen UID:
4693
Concept ID:
C0015934
Pathologic Function
An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.
Constipation
MedGen UID:
1101
Concept ID:
C0009806
Sign or Symptom
Infrequent or difficult evacuation of feces.
Feeding difficulties
MedGen UID:
65429
Concept ID:
C0232466
Finding
Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Hepatic steatosis
MedGen UID:
398225
Concept ID:
C2711227
Disease or Syndrome
Steatosis is a term used to denote lipid accumulation within hepatocytes.
Gastroesophageal reflux
MedGen UID:
1368658
Concept ID:
C4317146
Finding
A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter.
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).
Absent earlobe
MedGen UID:
341440
Concept ID:
C1849364
Anatomical Abnormality
Absence of fleshy non-cartilaginous tissue inferior to the tragus and incisura.
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 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.
Attention deficit hyperactivity disorder
MedGen UID:
220387
Concept ID:
C1263846
Mental or Behavioral Dysfunction
Attention-deficit/hyperactivity disorder (ADHD) is a behavioral disorder that typically begins in childhood and is characterized by a short attention span (inattention), an inability to be calm and stay still (hyperactivity), and poor impulse control (impulsivity). Some people with ADHD have problems with only inattention or with hyperactivity and impulsivity, but most have problems related to all three features.\n\nIn people with ADHD, the characteristic behaviors are frequent and severe enough to interfere with the activities of daily living such as school, work, and relationships with others. Because of an inability to stay focused on tasks, people with inattention may be easily distracted, forgetful, avoid tasks that require sustained attention, have difficulty organizing tasks, or frequently lose items.\n\nHyperactivity is usually shown by frequent movement. Individuals with this feature often fidget or tap their foot when seated, leave their seat when it is inappropriate to do so (such as in the classroom), or talk a lot and interrupt others.\n\nIn most affected individuals, ADHD continues throughout life, but in about one-third of individuals, signs and symptoms of ADHD go away by adulthood.\n\nImpulsivity can result in hasty actions without thought for the consequences. Individuals with poor impulse control may have difficulty waiting for their turn, deferring to others, or considering their actions before acting.\n\nMore than two-thirds of all individuals with ADHD have additional conditions, including insomnia, mood or anxiety disorders, learning disorders, or substance use disorders. Affected individuals may also have autism spectrum disorder, which is characterized by impaired communication and social interaction, or Tourette syndrome, which is a disorder characterized by repetitive and involuntary movements or noises called tics.
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.
Poor speech
MedGen UID:
341172
Concept ID:
C1848207
Finding
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.
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.
Retrognathia
MedGen UID:
19766
Concept ID:
C0035353
Congenital Abnormality
An abnormality in which the mandible is mislocalised posteriorly.
Frontal bossing
MedGen UID:
67453
Concept ID:
C0221354
Congenital Abnormality
Bilateral bulging of the lateral frontal bone prominences with relative sparing of the midline.
Joint contracture of the 5th finger
MedGen UID:
356345
Concept ID:
C1865702
Anatomical Abnormality
Chronic loss of joint motion in the 5th finger due to structural changes in non-bony tissue. The term camptodactyly of the 5th finger is used if the distal and/or proximal interphalangeal joints are affected.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Recurrent infections
MedGen UID:
65998
Concept ID:
C0239998
Finding
Increased susceptibility to infections.
Wide mouth
MedGen UID:
44238
Concept ID:
C0024433
Congenital Abnormality
Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective).
Bulbous nose
MedGen UID:
66013
Concept ID:
C0240543
Finding
Increased volume and globular shape of the anteroinferior aspect of the nose.
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).
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).
Full cheeks
MedGen UID:
355661
Concept ID:
C1866231
Finding
Increased prominence or roundness of soft tissues between zygomata and mandible.
Periorbital fullness
MedGen UID:
1710990
Concept ID:
C4760994
Finding
Increase in periorbital soft tissue.
Sparse hair
MedGen UID:
1790211
Concept ID:
C5551005
Finding
Reduced density of hairs.
Inversion of nipple
MedGen UID:
82844
Concept ID:
C0269269
Anatomical Abnormality
The presence of nipples that instead of pointing outward are retracted inwards.
Astigmatism
MedGen UID:
2473
Concept ID:
C0004106
Disease or Syndrome
Astigmatism (from the Greek 'a' meaning absence and 'stigma' meaning point) is a condition in which the parallel rays of light entering the eye through the refractive media are not focused on a single point. Both corneal and noncorneal factors contribute to refractive astigmatism. Corneal astigmatism is mainly the result of an aspheric anterior surface of the cornea, which can be measured readily by means of a keratometer; in a small fraction of cases (approximately 1 in 10) the effect is neutralized by the back surface. The curvature of the back surface of the cornea is not considered in most studies, because it is more difficult to measure; moreover, in the case of severe corneal astigmatism, there is evidence that both surfaces have the same configuration. Noncorneal factors are errors in the curvature of the 2 surfaces of the crystalline lens, irregularity in the refractive index of the lens, and an eccentric lens position. Since the cornea is the dominant component of the eye's refracting system, a highly astigmatic cornea is likely to result in a similarly astigmatic ocular refraction (summary by Clementi et al., 1998).
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).
Hypermetropia
MedGen UID:
43780
Concept ID:
C0020490
Disease or Syndrome
An abnormality of refraction characterized by the ability to see objects in the distance clearly, while objects nearby appear blurry.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
Strabismus
MedGen UID:
21337
Concept ID:
C0038379
Disease or Syndrome
A misalignment of the eyes so that the visual axes deviate from bifoveal fixation. The classification of strabismus may be based on a number of features including the relative position of the eyes, whether the deviation is latent or manifest, intermittent or constant, concomitant or otherwise and according to the age of onset and the relevance of any associated refractive error.
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.
Cerebral visual impairment
MedGen UID:
890568
Concept ID:
C4048268
Pathologic Function
A form of loss of vision caused by damage to the visual cortex rather than a defect in the eye.

Professional guidelines

PubMed

Wu C, Maegawa GHB, Zhang H
Brain Dev 2023 Oct;45(9):495-504. Epub 2023 Jun 9 doi: 10.1016/j.braindev.2023.05.006. PMID: 37302973
Ehninger D
Neuropharmacology 2013 May;68:97-105. Epub 2012 May 22 doi: 10.1016/j.neuropharm.2012.05.015. PMID: 22626986

Recent clinical studies

Etiology

Wojcik MH, Srivastava S, Agrawal PB, Balci TB, Callewaert B, Calvo PL, Carli D, Caudle M, Colaiacovo S, Cross L, Demetriou K, Drazba K, Dutra-Clarke M, Edwards M, Genetti CA, Grange DK, Hickey SE, Isidor B, Küry S, Lachman HM, Lavillaureix A, Lyons MJ, Marcelis C, Marco EJ, Martinez-Agosto JA, Nowak C, Pizzol A, Planes M, Prijoles EJ, Riberi E, Rush ET, Russell BE, Sachdev R, Schmalz B, Shears D, Stevenson DA, Wilson K, Jansen S, de Vries BBA, Curry CJ
Am J Med Genet A 2023 Jul;191(7):1900-1910. Epub 2023 May 14 doi: 10.1002/ajmg.a.63226. PMID: 37183572Free PMC Article
Carmona-Iragui M, Balasa M, Benejam B, Alcolea D, Fernández S, Videla L, Sala I, Sánchez-Saudinós MB, Morenas-Rodriguez E, Ribosa-Nogué R, Illán-Gala I, Gonzalez-Ortiz S, Clarimón J, Schmitt F, Powell DK, Bosch B, Lladó A, Rafii MS, Head E, Molinuevo JL, Blesa R, Videla S, Lleó A, Sánchez-Valle R, Fortea J
Alzheimers Dement 2017 Nov;13(11):1251-1260. Epub 2017 Apr 29 doi: 10.1016/j.jalz.2017.03.007. PMID: 28463681Free PMC Article
Bounakis N, Karampalis C, Sharp H, Tsirikos AI
J Med Case Rep 2015 Jan 18;9:10. doi: 10.1186/1752-1947-9-10. PMID: 25596810Free PMC Article
Zlotogora J
Am J Med Genet 1997 Feb 11;68(4):472-5. doi: 10.1002/(sici)1096-8628(19970211)68:4<472::aid-ajmg20>3.0.co;2-o. PMID: 9021024
Vogel F
Hum Genet 1979 Nov 1;52(1):1-54. doi: 10.1007/BF00284597. PMID: 393614

Diagnosis

Wu C, Maegawa GHB, Zhang H
Brain Dev 2023 Oct;45(9):495-504. Epub 2023 Jun 9 doi: 10.1016/j.braindev.2023.05.006. PMID: 37302973
Wojcik MH, Srivastava S, Agrawal PB, Balci TB, Callewaert B, Calvo PL, Carli D, Caudle M, Colaiacovo S, Cross L, Demetriou K, Drazba K, Dutra-Clarke M, Edwards M, Genetti CA, Grange DK, Hickey SE, Isidor B, Küry S, Lachman HM, Lavillaureix A, Lyons MJ, Marcelis C, Marco EJ, Martinez-Agosto JA, Nowak C, Pizzol A, Planes M, Prijoles EJ, Riberi E, Rush ET, Russell BE, Sachdev R, Schmalz B, Shears D, Stevenson DA, Wilson K, Jansen S, de Vries BBA, Curry CJ
Am J Med Genet A 2023 Jul;191(7):1900-1910. Epub 2023 May 14 doi: 10.1002/ajmg.a.63226. PMID: 37183572Free PMC Article
Pires LVL, Ribeiro RL, Sousa AM, Linnenkamp BDW, Pontes SE, Teixeira MCTV, Befi-Lopes DM, Honjo RS, Bertola DR, Kim CA
Arq Neuropsiquiatr 2021 Nov;79(11):950-956. doi: 10.1590/0004-282X-ANP-2020-0450. PMID: 34816986
Chen J, Xia Z, Zhou Y, Ma X, Wang X, Guo Q
BMC Med Genomics 2021 Mar 2;14(1):68. doi: 10.1186/s12920-021-00920-3. PMID: 33653342Free PMC Article
Moog U, van Mierlo I, van Schrojenstein Lantman-de Valk HM, Spaapen L, Maaskant MA, Curfs LM
Am J Med Genet C Semin Med Genet 2007 Aug 15;145C(3):293-301. doi: 10.1002/ajmg.c.30142. PMID: 17640047

Therapy

Ehninger D
Neuropharmacology 2013 May;68:97-105. Epub 2012 May 22 doi: 10.1016/j.neuropharm.2012.05.015. PMID: 22626986

Prognosis

Chen J, Xia Z, Zhou Y, Ma X, Wang X, Guo Q
BMC Med Genomics 2021 Mar 2;14(1):68. doi: 10.1186/s12920-021-00920-3. PMID: 33653342Free PMC Article
Bounakis N, Karampalis C, Sharp H, Tsirikos AI
J Med Case Rep 2015 Jan 18;9:10. doi: 10.1186/1752-1947-9-10. PMID: 25596810Free PMC Article
Moog U, van Mierlo I, van Schrojenstein Lantman-de Valk HM, Spaapen L, Maaskant MA, Curfs LM
Am J Med Genet C Semin Med Genet 2007 Aug 15;145C(3):293-301. doi: 10.1002/ajmg.c.30142. PMID: 17640047

Clinical prediction guides

Chen J, Xia Z, Zhou Y, Ma X, Wang X, Guo Q
BMC Med Genomics 2021 Mar 2;14(1):68. doi: 10.1186/s12920-021-00920-3. PMID: 33653342Free PMC Article
Bastaki F, Nair P, Mohamed M, Malik EM, Helmi M, Al-Ali MT, Hamzeh AR
BMC Med Genet 2017 Jun 15;18(1):68. doi: 10.1186/s12881-017-0429-0. PMID: 28619046Free PMC Article
Zlotogora J
Am J Med Genet 1997 Feb 11;68(4):472-5. doi: 10.1002/(sici)1096-8628(19970211)68:4<472::aid-ajmg20>3.0.co;2-o. PMID: 9021024
Say B, McCutcheon L, Todd C, Hough JV
Clin Dysmorphol 1993 Jan;2(1):68-70. PMID: 8298741
Vogel F
Hum Genet 1979 Nov 1;52(1):1-54. doi: 10.1007/BF00284597. PMID: 393614

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