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Severe X-linked myotubular myopathy(CNMX)

MedGen UID:
98374
Concept ID:
C0410203
Congenital Abnormality
Synonyms: CNMX; MYOPATHY, CENTRONUCLEAR, 1; MYOTUBULAR MYOPATHY 1; Myotubular myopathy, X-linked; X-linked centronuclear myopathy
Modes of inheritance:
X-linked recessive inheritance
MedGen UID:
375779
Concept ID:
C1845977
Finding
Sources: HPO, OMIM, 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.
X-linked recessive inheritance (HPO, OMIM, Orphanet)
SNOMED CT: X-linked centronuclear myopathy (46804001); Severe x-linked myotubular myopathy (46804001)
 
Gene (location): MTM1 (Xq28)
OMIM®: 310400
Orphanet: ORPHA596

Disease characteristics

Excerpted from the GeneReview: X-Linked Centronuclear Myopathy
X-linked centronuclear myopathy (XLCNM) (also known as myotubular myopathy [MTM]) is characterized by muscle weakness that ranges from severe to mild. Severe (classic) XLCNM presents prenatally with polyhydramnios and decreased fetal movement and in newborns with weakness, hypotonia, and respiratory distress. Affected males have significantly delayed motor milestones and most fail to achieve independent ambulation. Weakness is profound and often involves facial and extraocular muscles. Respiratory failure is nearly uniform, with most affected individuals requiring 24-hour ventilatory assistance. A minority of males with severe XLCNM die in infancy. Males with moderate XLCNM achieve motor milestones more quickly than males with the severe form; about 40% require no ventilator support or intermittent support. Males with mild XLCNM may require ventilatory support only in the newborn period; they have minimally delayed motor milestones, are able to walk, and may lack myopathic facies. The muscle disease of XLCNM is not obviously progressive. Female carriers of XLCNM are generally asymptomatic, although rare manifesting heterozygotes have been described. [from GeneReviews]
Authors:
Soma Das  |  James Dowling  |  Christopher R Pierson   view full author information

Additional description

From GHR
X-linked myotubular myopathy is a condition that primarily affects muscles used for movement (skeletal muscles) and occurs almost exclusively in males. People with this condition have muscle weakness (myopathy) and decreased muscle tone (hypotonia) that are usually evident at birth.The muscle problems in X-linked myotubular myopathy impair the development of motor skills such as sitting, standing, and walking. Affected infants may also have difficulties with feeding due to muscle weakness. Individuals with this condition often do not have the muscle strength to breathe on their own and must be supported with a machine to help them breathe (mechanical ventilation). Some affected individuals need breathing assistance only periodically, typically during sleep, while others require it continuously. People with X-linked myotubular myopathy may also have weakness in the muscles that control eye movement (ophthalmoplegia), weakness in other muscles of the face, and absent reflexes (areflexia).In X-linked myotubular myopathy, muscle weakness often disrupts normal bone development and can lead to fragile bones, an abnormal curvature of the spine (scoliosis), and joint deformities (contractures) of the hips and knees. People with X-linked myotubular myopathy may have a large head with a narrow and elongated face and a high, arched roof of the mouth (palate). They may also have liver disease, recurrent ear and respiratory infections, or seizures.Because of their severe breathing problems, individuals with X-linked myotubular myopathy usually survive only into early childhood; however, some people with this condition have lived into adulthood.X-linked myotubular myopathy is a member of a group of disorders called centronuclear myopathies. In centronuclear myopathies, the nucleus is found at the center of many rod-shaped muscle cells instead of at either end, where it is normally located.  https://ghr.nlm.nih.gov/condition/x-linked-myotubular-myopathy

Clinical features

Conduction disorder of the heart
MedGen UID:
78114
Concept ID:
C0264886
Disease or Syndrome
Abnormality in rhythm of heartbeat, including rate, regularity, and/or sequence of activation abnormalities
Ophthalmoparesis
MedGen UID:
155551
Concept ID:
C0751401
Sign or Symptom
Ophthalmoplegia is a paralysis or weakness of one or more of the muscles that control eye movement.
Ptosis
MedGen UID:
504471
Concept ID:
CN000475
Finding
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).
External ophthalmoplegia
MedGen UID:
504486
Concept ID:
CN000510
Finding
Paralysis of the external ocular muscles.
Cavernous hemangioma
MedGen UID:
9184
Concept ID:
C0018920
Neoplastic Process
The presence of a cavernous hemangioma. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma.
Arachnodactyly
MedGen UID:
2047
Concept ID:
C0003706
Congenital Abnormality
An abnormal bone development that is characterized by extra long and slender hands and fingers, such that the clenched thumb extends beyond the ulnar side of the hand. Arachnodactyly can include feet and toes. Arachnodactyly has been associated with several gene mutations and syndromes.
Slender toe
MedGen UID:
866814
Concept ID:
C4021168
Finding
Digits are disproportionately narrow (reduced girth) for the hand/foot size or build of the individual.
Cavernous hemangioma
MedGen UID:
9184
Concept ID:
C0018920
Neoplastic Process
The presence of a cavernous hemangioma. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma.
Conduction disorder of the heart
MedGen UID:
78114
Concept ID:
C0264886
Disease or Syndrome
Abnormality in rhythm of heartbeat, including rate, regularity, and/or sequence of activation abnormalities
Birth length greater than 97th percentile
MedGen UID:
326443
Concept ID:
C1839271
Finding
Diaphragmatic eventration
MedGen UID:
8359
Concept ID:
C0011981
Congenital Abnormality
A congenital abnormality characterized by the elevation of the DIAPHRAGM dome. It is the result of a thinned diaphragmatic muscle and injured PHRENIC NERVE, allowing the intra-abdominal viscera to push the diaphragm upward against the LUNG.
Pyloric stenosis
MedGen UID:
18780
Concept ID:
C0034194
Pathologic Function
An abnormal narrowing of the pylorus.
Decreased liver function
MedGen UID:
65430
Concept ID:
C0232744
Finding
Hydrocephalus
MedGen UID:
9335
Concept ID:
C0020255
Disease or Syndrome
Autosomal recessive nonsyndromic hydrocephalus is characterized by onset in utero of enlarged ventricles due to a disturbance of cerebrospinal fluid accumulation. Affected individuals may have neurologic impairment (summary by Drielsma et al., 2012). Hydrocephalus can also be caused by Arnold-Chiari malformation, atresia of foramen of Magendie, stenosis of aqueduct of Sylvius (307000), toxoplasmosis, hydranencephaly, etc. Furthermore, it develops in infancy or childhood in achondroplasia (100800) and in Hurler disease (607014). Genetic Heterogeneity of Congenital Hydrocephalus See also autosomal recessive HYC2 (615219), caused by mutation in the MPDZ gene (603785) on chromosome 9p. An X-linked form (307000) is caused by mutation in the L1CAM gene on (308840) on chromosome Xq28.
Seizures
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
Seizures are symptoms of a brain problem. They happen because of sudden, abnormal electrical activity in the brain. When people think of seizures, they often think of convulsions in which a person's body shakes rapidly and uncontrollably. Not all seizures cause convulsions. There are many types of seizures and some have mild symptoms. Seizures fall into two main groups. Focal seizures, also called partial seizures, happen in just one part of the brain. Generalized seizures are a result of abnormal activity on both sides of the brain. . Most seizures last from 30 seconds to 2 minutes and do not cause lasting harm. However, it is a medical emergency if seizures last longer than 5 minutes or if a person has many seizures and does not wake up between them. Seizures can have many causes, including medicines, high fevers, head injuries and certain diseases. People who have recurring seizures due to a brain disorder have epilepsy. . NIH: National Institute of Neurological Disorders and Stroke.
Absent tendon reflex
MedGen UID:
548673
Concept ID:
C0278124
Finding
Absence of neurologic reflexes such as the knee-jerk reaction.
Weakness of face muscles
MedGen UID:
98103
Concept ID:
C0427055
Sign or Symptom
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
Gait disturbance
MedGen UID:
107895
Concept ID:
C0575081
Finding
The term gait disturbance can refer to any disruption of the ability to walk. In general, this can refer to neurological diseases but also fractures or other sources of pain that is triggered upon walking. However, in the current context gait disturbance refers to difficulty walking on the basis of a neurological or muscular disease.
Reduced tendon reflexes
MedGen UID:
356648
Concept ID:
C1866934
Finding
Diminution of tendon reflexes, which is an invariable sign of peripheral nerve disease.
Hypokinesia
MedGen UID:
505216
Concept ID:
CN002157
Finding
Abnormally diminished motor activity. In contrast to paralysis, hypokinesia is not characterized by a lack of motor strength, but rather by a poverty of movement. The typical habitual movements (e.g., folding the arms, crossing the legs) are reduced in frequency.
Diaphragmatic eventration
MedGen UID:
8359
Concept ID:
C0011981
Congenital Abnormality
A congenital abnormality characterized by the elevation of the DIAPHRAGM dome. It is the result of a thinned diaphragmatic muscle and injured PHRENIC NERVE, allowing the intra-abdominal viscera to push the diaphragm upward against the LUNG.
Respiratory function loss
MedGen UID:
892404
Concept ID:
C4020855
Pathologic Function
Failure to adequately provide oxygen to cells of the body and to remove excess carbon dioxide.
Diaphragmatic eventration
MedGen UID:
8359
Concept ID:
C0011981
Congenital Abnormality
A congenital abnormality characterized by the elevation of the DIAPHRAGM dome. It is the result of a thinned diaphragmatic muscle and injured PHRENIC NERVE, allowing the intra-abdominal viscera to push the diaphragm upward against the LUNG.
Pyloric stenosis
MedGen UID:
18780
Concept ID:
C0034194
Pathologic Function
An abnormal narrowing of the pylorus.
Decreased liver function
MedGen UID:
65430
Concept ID:
C0232744
Finding
Muscular hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
A diminution of the skeletal muscle tone marked by a diminished resistance to passive stretching.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
Decreased strength of the neck musculature.
Denervation atrophy of muscle
MedGen UID:
78748
Concept ID:
C0270948
Pathologic Function
The presence of skeletal muscular atrophy (which is also known as amyotrophy).
Weakness of face muscles
MedGen UID:
98103
Concept ID:
C0427055
Sign or Symptom
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
EMG abnormality
MedGen UID:
99199
Concept ID:
C0476403
Finding
Abnormal results of investigations using electromyography (EMG).
Generalized muscle weakness
MedGen UID:
155433
Concept ID:
C0746674
Sign or Symptom
Generalized weakness or decreased strength of the muscles, affecting both distal and proximal musculature.
Severe muscular hypotonia
MedGen UID:
326544
Concept ID:
C1839630
Finding
A severe degree of muscular hypotonia characterized by markedly reduced muscle tone.
Flexion contracture
MedGen UID:
892408
Concept ID:
C2117118
Finding
Arachnodactyly
MedGen UID:
2047
Concept ID:
C0003706
Congenital Abnormality
An abnormal bone development that is characterized by extra long and slender hands and fingers, such that the clenched thumb extends beyond the ulnar side of the hand. Arachnodactyly can include feet and toes. Arachnodactyly has been associated with several gene mutations and syndromes.
Scoliosis
MedGen UID:
195976
Concept ID:
C0700208
Finding
The presence of an abnormal lateral curvature of the spine.
Flexion contracture
MedGen UID:
892408
Concept ID:
C2117118
Finding
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Macrocephaly refers to an abnormally enlarged head inclusive of the scalp, cranial bones, and intracranial contents. Macrocephaly may be due to megalencephaly (true enlargement of the brain parenchyma), and the 2 terms are often used interchangeably in the genetic literature (reviews by Olney, 2007 and Williams et al., 2008). Autosomal recessive macrocephaly/megalencephaly syndrome is characterized by an enlarged cranium apparent at birth or in early childhood. Affected individuals have intellectual disability and may have dysmorphic facial features resulting from the macrocephaly (summary by Alfaiz et al., 2014).
Slender toe
MedGen UID:
866814
Concept ID:
C4021168
Finding
Digits are disproportionately narrow (reduced girth) for the hand/foot size or build of the individual.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
Decreased strength of the neck musculature.
Mask-like facies
MedGen UID:
140860
Concept ID:
C0424448
Finding
A lack of facial expression often with staring eyes and a slightly open mouth.
Weakness of face muscles
MedGen UID:
98103
Concept ID:
C0427055
Sign or Symptom
Facial nerve palsy is a dysfunction of cranial nerve VII (the facial nerve) that results in inability to control facial muscles on the affected side with weakness of the muscles of facial expression and eye closure. This can either be present in unilateral or bilateral form.
Long face
MedGen UID:
324419
Concept ID:
C1836047
Anatomical Abnormality
Facial height (length) is more than 2 standard deviations above the mean (objective); or, an apparent increase in the height (length) of the face (subjective).
Narrow face
MedGen UID:
373334
Concept ID:
C1837463
Finding
Bizygomatic (upper face) and bigonial (lower face) width are both more than 2 standard deviations below the mean (objective); or, an apparent reduction in the width of the upper and lower face (subjective).
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Macrocephaly refers to an abnormally enlarged head inclusive of the scalp, cranial bones, and intracranial contents. Macrocephaly may be due to megalencephaly (true enlargement of the brain parenchyma), and the 2 terms are often used interchangeably in the genetic literature (reviews by Olney, 2007 and Williams et al., 2008). Autosomal recessive macrocephaly/megalencephaly syndrome is characterized by an enlarged cranium apparent at birth or in early childhood. Affected individuals have intellectual disability and may have dysmorphic facial features resulting from the macrocephaly (summary by Alfaiz et al., 2014).
High palate
MedGen UID:
504397
Concept ID:
CN000211
Finding
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).
Flexion contracture
MedGen UID:
892408
Concept ID:
C2117118
Finding
Cavernous hemangioma
MedGen UID:
9184
Concept ID:
C0018920
Neoplastic Process
The presence of a cavernous hemangioma. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma.
Decreased fetal movement
MedGen UID:
68618
Concept ID:
C0235659
Finding
An abnormal reduction in quantity or strength of fetal movements.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
Follow this link to review classifications for Severe X-linked myotubular myopathy in Orphanet.

Professional guidelines

PubMed

Biancalana V, Beggs AH, Das S, Jungbluth H, Kress W, Nishino I, North K, Romero NB, Laporte J
Eur J Hum Genet 2012 Oct;20(10) Epub 2012 May 23 doi: 10.1038/ejhg.2012.91. [Epub ahead of print] PMID: 22617344Free PMC Article

Recent clinical studies

Prognosis

Tyson RW, Ringel SP, Manchester DK, Shikes RH, Goodman SI
Pediatr Pathol 1992 Jul-Aug;12(4):535-43. PMID: 1409152

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