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X-linked lissencephaly with abnormal genitalia(XLAG; LISX2)

MedGen UID:
375832
Concept ID:
C1846171
Disease or Syndrome
Synonyms: Lissencephaly 2, X-linked; X-Linked Lissencephaly with Ambiguous Genitalia
SNOMED CT: X-linked lissencephaly with abnormal genitalia syndrome (717632002); X-linked lissencephaly with ambiguous genitalia (717632002); X-linked lissencephaly with agenesis of corpus callosum and genital anomaly syndrome (717632002)
Modes of inheritance:
X-linked recessive inheritance
MedGen UID:
375779
Concept ID:
C1845977
Finding
Source: Orphanet
A mode of inheritance that is observed for recessive traits related to a gene encoded on the X chromosome. In the context of medical genetics, X-linked recessive disorders manifest in males (who have one copy of the X chromosome and are thus hemizygotes), but generally not in female heterozygotes who have one mutant and one normal allele.
 
Gene (location): ARX (Xp21.3)
 
Monarch Initiative: MONDO:0010268
OMIM®: 300215
Orphanet: ORPHA452

Definition

X-linked lissencephaly-2 (LISX2) is a developmental disorder characterized by structural brain anomalies, early-onset intractable seizures, severe psychomotor retardation, and ambiguous genitalia. Males are severely affected and often die within the first days or months of life, whereas females may be unaffected or have a milder phenotype (Bonneau et al., 2002). LISX2 is part of a phenotypic spectrum of disorders caused by mutation in the ARX gene comprising a nearly continuous series of developmental disorders ranging from hydranencephaly and lissencephaly to Proud syndrome (300004) to infantile spasms without brain malformations (DEE1; 308350) to syndromic (309510) and nonsyndromic (300419) mental retardation (Kato et al., 2004; Wallerstein et al., 2008). For a general phenotypic description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432). [from OMIM]

Additional description

From MedlinePlus Genetics
X-linked lissencephaly with abnormal genitalia (XLAG) is a condition that affects the development of the brain and genitalia. It occurs most often in males.

XLAG is characterized by abnormal brain development that results in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. Individuals without any folds in the brain (agyria) typically have more severe symptoms than people with reduced folds and grooves (pachygyria). Individuals with XLAG may also have a lack of development (agenesis) of the tissue connecting the left and right halves of the brain (corpus callosum). 

In XLAG, the brain abnormalities can cause severe intellectual disability and developmental delay, abnormal muscle stiffness (spasticity), weak muscle tone (hypotonia), and feeding difficulties. Starting soon after birth, babies with XLAG have frequent and recurrent seizures (epilepsy). Most children with XLAG do not survive past early childhood.

Another key feature of XLAG in males is abnormal genitalia that can include an unusually small penis (micropenis), undescended testes (cryptorchidism), or external genitalia that do not look clearly male or clearly female.

Additional signs and symptoms of XLAG include chronic diarrhea, periods of increased blood glucose (transient hyperglycemia), and problems with body temperature regulation.  https://medlineplus.gov/genetics/condition/x-linked-lissencephaly-with-abnormal-genitalia

Clinical features

From HPO
Decreased testicular size
MedGen UID:
66027
Concept ID:
C0241355
Finding
Reduced volume of the testicle (the male gonad).
Ambiguous genitalia
MedGen UID:
78596
Concept ID:
C0266362
Congenital Abnormality
A genital phenotype that is not clearly assignable to a single gender. Ambiguous genitalia can be evaluated using the Prader scale
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.
Diarrhea
MedGen UID:
8360
Concept ID:
C0011991
Sign or Symptom
Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day.
Feeding difficulties in infancy
MedGen UID:
436211
Concept ID:
C2674608
Finding
Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention.
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.
Gliosis
MedGen UID:
4899
Concept ID:
C0017639
Pathologic Function
Gliosis is the focal proliferation of glial cells in the central nervous system.
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.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterised by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Hyperreflexia
MedGen UID:
57738
Concept ID:
C0151889
Finding
Hyperreflexia is the presence of hyperactive stretch reflexes of the muscles.
Corpus callosum, agenesis of
MedGen UID:
104498
Concept ID:
C0175754
Congenital Abnormality
The corpus callosum is the largest fiber tract in the central nervous system and the major interhemispheric fiber bundle in the brain. Formation of the corpus callosum begins as early as 6 weeks' gestation, with the first fibers crossing the midline at 11 to 12 weeks' gestation, and completion of the basic shape by age 18 to 20 weeks (Schell-Apacik et al., 2008). Agenesis of the corpus callosum (ACC) is one of the most frequent malformations in brain with a reported incidence ranging between 0.5 and 70 in 10,000 births. ACC is a clinically and genetically heterogeneous condition, which can be observed either as an isolated condition or as a manifestation in the context of a congenital syndrome (see MOLECULAR GENETICS and Dobyns, 1996). Also see mirror movements-1 and/or agenesis of the corpus callosum (MRMV1; 157600). Schell-Apacik et al. (2008) noted that there is confusion in the literature regarding radiologic terminology concerning partial absence of the corpus callosum, where various designations have been used, including hypogenesis, hypoplasia, partial agenesis, or dysgenesis.
Lissencephaly
MedGen UID:
78604
Concept ID:
C0266463
Finding
A spectrum of malformations of cortical development caused by insufficient neuronal migration that subsumes the terms agyria, pachygyria and subcortical band heterotopia. See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly.
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.
Ventriculomegaly
MedGen UID:
480553
Concept ID:
C3278923
Finding
An increase in size of the ventricular system of the brain.
Profound global developmental delay
MedGen UID:
766364
Concept ID:
C3553450
Disease or Syndrome
A profound delay in the achievement of motor or mental milestones in the domains of development of a child.
Specific learning disability
MedGen UID:
871302
Concept ID:
C4025790
Mental or Behavioral Dysfunction
Impairment of certain skills such as reading or writing, coordination, self-control, or attention that interfere with the ability to learn. The impairment is not related to a global deficiency of intelligence.
Pachygyria
MedGen UID:
504794
Concept ID:
CN001193
Finding
Pachygyria is a malformation of cortical development with abnormally wide gyri with sulci 1,5-3 cm apart and abnormally thick cortex measuring more than 5 mm (radiological definition). See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly.
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.
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Wide anterior fontanel
MedGen UID:
400926
Concept ID:
C1866134
Finding
Enlargement of the anterior fontanelle with respect to age-dependent norms.
High forehead
MedGen UID:
65991
Concept ID:
C0239676
Finding
An abnormally increased height of the forehead.
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).
Wide nasal bridge
MedGen UID:
341441
Concept ID:
C1849367
Finding
Increased breadth of the nasal bridge (and with it, the nasal root).
Prominent nasal bridge
MedGen UID:
343051
Concept ID:
C1854113
Finding
Anterior positioning of the nasal root in comparison to the usual positioning for age.
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).
Long upper lip
MedGen UID:
462845
Concept ID:
C3151495
Finding
Increased width of the upper lip.
Duane retraction syndrome
MedGen UID:
4413
Concept ID:
C0013261
Disease or Syndrome
Duane syndrome is a strabismus condition clinically characterized by congenital non-progressive limited horizontal eye movement accompanied by globe retraction which results in narrowing of the palpebral fissure. The lateral movement anomaly results from failure of the abducens nucleus and nerve (cranial nerve VI) to fully innervate the lateral rectus muscle; globe retraction occurs as a result of abnormal innervation of the lateral rectus muscle by the oculomotor nerve (cranial nerve III). At birth, affected infants have restricted ability to move the affected eye(s) outward (abduction) and/or inward (adduction), though the limitations may not be recognized in early infancy. In addition, the globe retracts into the orbit with attempted adduction, accompanied by narrowing of the palpebral fissure. Many individuals with Duane syndrome have strabismus in primary gaze but can use a compensatory head turn to align the eyes, and thus can preserve binocular vision and avoid diplopia. Individuals with Duane syndrome who lack binocular vision are at risk for amblyopia. The majority of affected individuals with Duane syndrome have isolated Duane syndrome (i.e., they do not have other detected congenital anomalies). Other individuals with Duane syndrome fall into well-defined syndromic diagnoses. However, many individuals with Duane syndrome have non-ocular findings that do not fit a known syndrome; these individuals are included as part of the discussion of nonsyndromic Duane syndrome.

Term Hierarchy

Follow this link to review classifications for X-linked lissencephaly with abnormal genitalia in Orphanet.

Professional guidelines

PubMed

Poirier K, Lacombe D, Gilbert-Dussardier B, Raynaud M, Desportes V, de Brouwer AP, Moraine C, Fryns JP, Ropers HH, Beldjord C, Chelly J, Bienvenu T
Neurogenetics 2006 Mar;7(1):39-46. Epub 2005 Oct 19 doi: 10.1007/s10048-005-0014-0. PMID: 16235064
Kato M, Das S, Petras K, Kitamura K, Morohashi KI, Abuelo DN, Barr M, Bonneau D, Brady AF, Carpenter NJ, Cipero KL, Frisone F, Fukuda T, Guerrini R, Iida E, Itoh M, Lewanda AF, Nanba Y, Oka A, Proud VK, Saugier-Veber P, Schelley SL, Selicorni A, Shaner R, Silengo M, Stewart F, Sugiyama N, Toyama J, Toutain A, Vargas AL, Yanazawa M, Zackai EH, Dobyns WB
Hum Mutat 2004 Feb;23(2):147-159. doi: 10.1002/humu.10310. PMID: 14722918

Recent clinical studies

Clinical prediction guides

Curie A, Friocourt G, des Portes V, Roy A, Nazir T, Brun A, Cheylus A, Marcorelles P, Retzepi K, Maleki N, Bussy G, Paulignan Y, Reboul A, Ibarrola D, Kong J, Hadjikhani N, Laquerrière A, Gollub RL
Neuroimage Clin 2018;19:454-465. Epub 2018 Apr 5 doi: 10.1016/j.nicl.2018.04.001. PMID: 29984154Free PMC Article

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