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Developmental and epileptic encephalopathy 89(DEE89)

MedGen UID:
1761611
Concept ID:
C5436853
Disease or Syndrome
Synonyms: DEE89; DEVELOPMENTAL AND EPILEPTIC ENCEPHALOPATHY 89
 
Gene (location): GAD1 (2q31.1)
 
Monarch Initiative: MONDO:0030856
OMIM®: 619124

Definition

Developmental and epileptic encephalopathy-89 (DEE89) is a severe autosomal recessive disorder characterized by profound global developmental delay with impaired intellectual development, absent speech, inability to sit or walk due to axial hypotonia and spastic quadriparesis, and onset of seizures in the first days or months of life. EEG shows suppression-burst pattern or hypsarrhythmia, consistent with DEE or a clinical diagnosis of West syndrome. More variable features include joint contractures with foot deformities, dysmorphic facial features with cleft palate, and omphalocele. Affected individuals have poor motor skills, poor eye contact, and lack of language development; some die in infancy or early childhood. Brain imaging may be normal or show nonspecific abnormalities (summary by Chatron et al., 2020). [from OMIM]

Clinical features

From HPO
Clitoral hypertrophy
MedGen UID:
57848
Concept ID:
C0156394
Finding
Hypertrophy of the clitoris.
Hypoplastic labia majora
MedGen UID:
107566
Concept ID:
C0566899
Finding
Undergrowth of the outer labia.
Hypoplastic labia minora
MedGen UID:
376558
Concept ID:
C1849295
Finding
Clubfoot
MedGen UID:
3130
Concept ID:
C0009081
Congenital Abnormality
Clubfoot is a congenital limb deformity defined as fixation of the foot in cavus, adductus, varus, and equinus (i.e., inclined inwards, axially rotated outwards, and pointing downwards) with concomitant soft tissue abnormalities (Cardy et al., 2007). Clubfoot may occur in isolation or as part of a syndrome (e.g., diastrophic dysplasia, 222600). Clubfoot has been reported with deficiency of long bones and mirror-image polydactyly (Gurnett et al., 2008; Klopocki et al., 2012).
Limb undergrowth
MedGen UID:
116086
Concept ID:
C0239399
Finding
Limb shortening because of underdevelopment of one or more bones of the extremities.
Low-set ears
MedGen UID:
65980
Concept ID:
C0239234
Congenital Abnormality
Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear.
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.
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.
Spasticity
MedGen UID:
7753
Concept ID:
C0026838
Sign or Symptom
A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Cerebral atrophy
MedGen UID:
116012
Concept ID:
C0235946
Disease or Syndrome
Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.
Tetraparesis
MedGen UID:
78731
Concept ID:
C0270790
Finding
Weakness of all four limbs.
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.
Hypsarrhythmia
MedGen UID:
195766
Concept ID:
C0684276
Finding
Hypsarrhythmia is abnormal interictal high amplitude waves and a background of irregular spikes. There is continuous (during wakefulness), high-amplitude (>200 Hz), generalized polymorphic slowing with no organized background and multifocal spikes demonstrated by electroencephalography (EEG).
Cerebellar atrophy
MedGen UID:
196624
Concept ID:
C0740279
Disease or Syndrome
Cerebellar atrophy is defined as a cerebellum with initially normal structures, in a posterior fossa with normal size, which displays enlarged fissures (interfolial spaces) in comparison to the foliae secondary to loss of tissue. Cerebellar atrophy implies irreversible loss of tissue and result from an ongoing progressive disease until a final stage is reached or a single injury, e.g. an intoxication or infectious event.
Epileptic spasm
MedGen UID:
315948
Concept ID:
C1527366
Disease or Syndrome
A sudden flexion, extension, or mixed extension-flexion of predominantly proximal and truncal muscles that is usually more sustained than a myoclonic movement but not as sustained as a tonic seizure. Limited forms may occur
EEG with burst suppression
MedGen UID:
369943
Concept ID:
C1969156
Finding
The burst suppression pattern in electroencephalography refers to a characteristic periodic pattern of low voltage (<10 microvolts) suppressed background and a relatively shorter pattern of higher amplitude slow, sharp, and spiking complexes.
Intellectual disability, profound
MedGen UID:
892508
Concept ID:
C3161330
Mental or Behavioral Dysfunction
Profound mental retardation is defined as an intelligence quotient (IQ) below 20.
Hyperkinetic movements
MedGen UID:
854367
Concept ID:
C3887506
Disease or Syndrome
Motor hyperactivity with excessive movement of muscles of the body as a whole.
Myoclonic seizure
MedGen UID:
1385980
Concept ID:
C4317123
Sign or Symptom
A myoclonic seizure is a type of motor seizure characterized by sudden, brief (<100 ms) involuntary single or multiple contraction of muscles or muscle groups of variable topography (axial, proximal limb, distal). Myoclonus is less regularly repetitive and less sustained than is clonus.
Bilateral tonic-clonic seizure with generalized onset
MedGen UID:
1368929
Concept ID:
C4476643
Sign or Symptom
A bilateral tonic-clonic seizure with generalized onset is a type of bilateral tonic-clonic seizure characterized by generalized onset; these seizures rapidly engage networks in both hemispheres at the start of the seizure.
Hypertonia
MedGen UID:
10132
Concept ID:
C0026826
Finding
A condition in which there is increased muscle tone so that arms or legs, for example, are stiff and difficult to move.
Scoliosis
MedGen UID:
11348
Concept ID:
C0036439
Disease or Syndrome
The presence of an abnormal lateral curvature of the spine.
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.
Narrow chest
MedGen UID:
96528
Concept ID:
C0426790
Finding
Reduced width of the chest from side to side, associated with a reduced distance from the sternal notch to the tip of the shoulder.
Congenital omphalocele
MedGen UID:
162756
Concept ID:
C0795690
Congenital Abnormality
An omphalocele is an abdominal wall defect limited to an open umbilical ring, and is characterized by the herniation of membrane-covered internal organs into the open base of the umbilical cord. Omphalocele is distinguished from gastroschisis (230750), in which the abdominal wall defect is located laterally to a normally closed umbilical ring with herniation of organs that are uncovered by membranes (summary by Bugge, 2010). On the basis of clinical manifestations, epidemiologic characteristics, and the presence of additional malformations, Yang et al. (1992) concluded that omphalocele and gastroschisis are casually and pathogenetically distinct abdominal wall defects. Omphalocele can be a feature of genetic disorders, such as Beckwith-Wiedemann syndrome (130650) and the Shprintzen-Goldberg syndrome (182210).
Microretrognathia
MedGen UID:
326907
Concept ID:
C1839546
Finding
A form of developmental hypoplasia of the mandible in which the mandible is mislocalised posteriorly.
Axial hypotonia
MedGen UID:
342959
Concept ID:
C1853743
Finding
Muscular hypotonia (abnormally low muscle tone) affecting the musculature of the trunk.
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.
Upslanted palpebral fissure
MedGen UID:
98390
Concept ID:
C0423109
Finding
The palpebral fissure inclination is more than two standard deviations above the mean for age (objective); or, the inclination of the palpebral fissure is greater than typical for age.
Downslanted palpebral fissures
MedGen UID:
98391
Concept ID:
C0423110
Finding
The palpebral fissure inclination is more than two standard deviations below the mean.
Smooth philtrum
MedGen UID:
222980
Concept ID:
C1142533
Finding
Flat skin surface, with no ridge formation in the central region of the upper lip between the nasal base and upper vermilion border.
Sparse eyebrow
MedGen UID:
371332
Concept ID:
C1832446
Finding
Decreased density/number of eyebrow hairs.
Depressed nasal bridge
MedGen UID:
373112
Concept ID:
C1836542
Finding
Posterior positioning of the nasal root in relation to the overall facial profile for age.
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).
Wide nasal bridge
MedGen UID:
341441
Concept ID:
C1849367
Finding
Increased breadth of the nasal bridge (and with it, the nasal root).
Flat face
MedGen UID:
342829
Concept ID:
C1853241
Finding
Absence of concavity or convexity of the face when viewed in profile.
Long philtrum
MedGen UID:
351278
Concept ID:
C1865014
Finding
Distance between nasal base and midline upper lip vermilion border more than 2 SD above the mean. Alternatively, an apparently increased distance between nasal base and midline upper lip vermilion border.
Thin upper lip vermilion
MedGen UID:
355352
Concept ID:
C1865017
Finding
Height of the vermilion of the upper lip in the midline more than 2 SD below the mean. Alternatively, an apparently reduced height of the vermilion of the upper lip in the frontal view (subjective).
Highly arched eyebrow
MedGen UID:
358357
Concept ID:
C1868571
Finding
Increased height of the central portion of the eyebrow, forming a crescent, semicircular, or inverted U shape.
Cleft palate
MedGen UID:
756015
Concept ID:
C2981150
Congenital Abnormality
Cleft palate is a developmental defect of the palate resulting from a failure of fusion of the palatine processes and manifesting as a separation of the roof of the mouth (soft and hard palate).
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).

Professional guidelines

PubMed

Zou W, Li M, Wang X, Lu H, Hao Y, Chen D, Zhu S, Ji D, Zhang Z, Zhou P, Cao Y
J Assist Reprod Genet 2024 May;41(5):1245-1259. Epub 2024 Mar 12 doi: 10.1007/s10815-024-03057-1. PMID: 38470552Free PMC Article
Kessi M, Chen B, Shan LD, Wang Y, Yang L, Yin F, He F, Peng J, Wang G
BMC Med Genomics 2023 Mar 7;16(1):46. doi: 10.1186/s12920-023-01474-2. PMID: 36882827Free PMC Article
Sánchez Fernández I, Abend NS, Amengual-Gual M, Anderson A, Arya R, Barcia Aguilar C, Brenton JN, Carpenter JL, Chapman KE, Clark J, Farias-Moeller R, Gaillard WD, Gaínza-Lein M, Glauser T, Goldstein J, Goodkin HP, Guerriero RM, Lai YC, McDonough T, Mikati MA, Morgan LA, Novotny E Jr, Payne E, Peariso K, Piantino J, Ostendorf A, Sands TT, Sannagowdara K, Tasker RC, Tchapyjnikov D, Topjian AA, Vasquez A, Wainwright MS, Wilfong A, Williams K, Loddenkemper T; pSERG
Neurology 2020 Sep 1;95(9):e1222-e1235. Epub 2020 Jul 1 doi: 10.1212/WNL.0000000000010174. PMID: 32611646Free PMC Article

Recent clinical studies

Diagnosis

Khorram E, Amini M, Khorrami M
Epilepsia Open 2023 Jun;8(2):571-585. Epub 2023 Apr 17 doi: 10.1002/epi4.12739. PMID: 37029735Free PMC Article

Prognosis

Khorram E, Amini M, Khorrami M
Epilepsia Open 2023 Jun;8(2):571-585. Epub 2023 Apr 17 doi: 10.1002/epi4.12739. PMID: 37029735Free PMC Article

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