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Severe X-linked myotubular myopathy(CNMX)

MedGen UID:
98374
Concept ID:
C0410203
Congenital Abnormality
Synonyms: CNMX; MYOPATHY, CENTRONUCLEAR, 1; MYOPATHY, CENTRONUCLEAR, X-LINKED; MYOTUBULAR MYOPATHY 1; Myotubular Myopathy, X-Linked; Myotubular myopathy, X-linked; X-linked centronuclear myopathy; X-linked myotubular myopathy
Modes of inheritance:
X-linked recessive inheritance
MedGen UID:
425042
Concept ID:
CN001297
Genetic Function
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.
SNOMED CT: X-linked centronuclear myopathy (46804001); Severe x-linked myotubular myopathy (46804001)
 
Gene: MTM1
Cytogenetic location: 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]
Full text of GeneReview (by section):
Summary  |  Diagnosis  |  Clinical Description  |  Differential Diagnosis  |  Management  |  Genetic Counseling  |  Resources  |  Molecular Genetics  |  References  |  Chapter Notes
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.  http://ghr.nlm.nih.gov/condition/x-linked-myotubular-myopathy

Clinical features

Birth length greater than 97th percentile
MedGen UID:
326443
Concept ID:
C1839271
Finding
Cavernous hemangioma
MedGen UID:
504697
Concept ID:
CN000983
Finding
The presence of a cavernous hemangioma. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma.
Cryptorchidism
MedGen UID:
504309
Concept ID:
CN000029
Finding
Absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the testis.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
Mask-like facies
MedGen UID:
140860
Concept ID:
C0424448
Finding
Long face
MedGen UID:
324419
Concept ID:
C1836047
Finding
Narrow face
MedGen UID:
373334
Concept ID:
C1837463
Finding
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
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).
Facial palsy
MedGen UID:
506391
Concept ID:
CN009454
Finding
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.
Ophthalmoparesis
MedGen UID:
463310
Concept ID:
C3151960
Finding
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.
Areflexia
MedGen UID:
115943
Concept ID:
C0234146
Finding
Gait disturbance
MedGen UID:
333349
Concept ID:
C1839568
Finding
Hypokinesia
MedGen UID:
374267
Concept ID:
C1839631
Finding
Seizures
MedGen UID:
409523
Concept ID:
C1959629
Finding
Hydrocephalus
MedGen UID:
369747
Concept ID:
C1963137
Finding
Reduced tendon reflexes
MedGen UID:
427865
Concept ID:
CN001205
Finding
Diminution of tendon reflexes, which is an invariable sign of peripheral nerve disease.
Facial palsy
MedGen UID:
506391
Concept ID:
CN009454
Finding
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.
Arachnodactyly
MedGen UID:
371636
Concept ID:
C1833730
Finding
Macrocephaly
MedGen UID:
745757
Concept ID:
C2243051
Finding
Flexion contracture
MedGen UID:
504817
Concept ID:
CN001256
Finding
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.
Scoliosis
MedGen UID:
427922
Concept ID:
CN002409
Finding
The presence of an abnormal lateral curvature of the spine.
Slender toe
MedGen UID:
489128
Concept ID:
CN167036
Finding
Digits are disproportionately narrow (reduced girth) for the hand/foot size or build of the individual.
Decreased fetal movement
MedGen UID:
68618
Concept ID:
C0235659
Finding
Polyhydramnios
MedGen UID:
504854
Concept ID:
CN001423
Finding
The presence of excess amniotic fluid in the uterus during pregnancy.
Pyloric stenosis
MedGen UID:
18780
Concept ID:
C0034194
Finding
Narrowing of the pyloric canal with varied etiology. A common form is due to muscle hypertrophy (PYLORIC STENOSIS, HYPERTROPHIC) seen in infants.
Decreased liver function
MedGen UID:
504835
Concept ID:
CN001291
Finding
Reduced ability of the liver to perform its functions.
Diaphragmatic eventration
MedGen UID:
506289
Concept ID:
CN008001
Finding
A congenital failure of muscular development of part or all of one or both hemidiaphragms, resulting in superior displacement of abdominal viscera and altered lung development.
Cavernous hemangioma
MedGen UID:
504697
Concept ID:
CN000983
Finding
The presence of a cavernous hemangioma. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma.
Arrhythmia
MedGen UID:
66750
Concept ID:
C0237314
Finding
Cavernous hemangioma
MedGen UID:
504697
Concept ID:
CN000983
Finding
The presence of a cavernous hemangioma. A hemangioma characterized by large endothelial spaces (caverns) is called a cavernous hemangioma.
Respiratory insufficiency
MedGen UID:
155440
Concept ID:
C0748358
Finding
Neonatal respiratory distress
MedGen UID:
505314
Concept ID:
CN002404
Finding
Respiratory difficulty as newborn.
Respiratory failure requiring assisted ventilation
MedGen UID:
505713
Concept ID:
CN004331
Finding
Diaphragmatic eventration
MedGen UID:
506289
Concept ID:
CN008001
Finding
A congenital failure of muscular development of part or all of one or both hemidiaphragms, resulting in superior displacement of abdominal viscera and altered lung development.
Neck muscle weakness
MedGen UID:
66808
Concept ID:
C0240479
Finding
EMG abnormality
MedGen UID:
99199
Concept ID:
C0476403
Finding
Severe muscular hypotonia
MedGen UID:
326544
Concept ID:
C1839630
Finding
Generalized muscle weakness
MedGen UID:
334473
Concept ID:
C1843698
Finding
Amyotrophy
MedGen UID:
346831
Concept ID:
C1858480
Finding
Muscular hypotonia
MedGen UID:
504768
Concept ID:
CN001147
Finding
Muscular hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle), often involving reduced muscle strength. Hypotonia is characterized by a diminished resistance to passive stretching.
Flexion contracture
MedGen UID:
504817
Concept ID:
CN001256
Finding
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.
Facial palsy
MedGen UID:
506391
Concept ID:
CN009454
Finding
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.
Flexion contracture
MedGen UID:
504817
Concept ID:
CN001256
Finding
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.
Arachnodactyly
MedGen UID:
371636
Concept ID:
C1833730
Finding
Slender toe
MedGen UID:
489128
Concept ID:
CN167036
Finding
Digits are disproportionately narrow (reduced girth) for the hand/foot size or build of the individual.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews

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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