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Megaconial type congenital muscular dystrophy(MDCMC)

MedGen UID:
355943
Concept ID:
C1865233
Disease or Syndrome
Synonyms: CHKB-Related Muscle Diseases; MDCMC; MUSCULAR DYSTROPHY, CONGENITAL, WITH MITOCHONDRIAL STRUCTURAL ABNORMALITIES
SNOMED CT: Congenital muscular dystrophy with mitochondrial structural abnormalities (1230273004); Megaconial congenital muscular dystrophy (1230273004); Congenital megaconial myopathy (1230273004); Congenital muscular dystrophy due to phosphatidylcholine biosynthesis defect (1230273004)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): CHKB (22q13.33)
 
Monarch Initiative: MONDO:0011246
OMIM®: 602541
Orphanet: ORPHA280671

Definition

Megaconial-type congenital muscular dystrophy (MDCMC) is an autosomal recessive disorder characterized by early-onset muscle wasting and impaired intellectual development. Some patients develop fatal cardiomyopathy. Muscle biopsy shows peculiar enlarged mitochondria that are prevalent toward the periphery of the fibers but are sparse in the center (summary by Mitsuhashi et al., 2011). [from OMIM]

Clinical features

From HPO
Primary dilated cardiomyopathy
MedGen UID:
2880
Concept ID:
C0007193
Disease or Syndrome
Familial dilated cardiomyopathy is a genetic form of heart disease. It occurs when heart (cardiac) muscle becomes thin and weakened in at least one chamber of the heart, causing the open area of the chamber to become enlarged (dilated). As a result, the heart is unable to pump blood as efficiently as usual. To compensate, the heart attempts to increase the amount of blood being pumped through the heart, leading to further thinning and weakening of the cardiac muscle. Over time, this condition results in heart failure.\n\nIt usually takes many years for symptoms of familial dilated cardiomyopathy to cause health problems. They typically begin in mid-adulthood, but can occur at any time from infancy to late adulthood. Signs and symptoms of familial dilated cardiomyopathy can include an irregular heartbeat (arrhythmia), shortness of breath (dyspnea), extreme tiredness (fatigue), fainting episodes (syncope), and swelling of the legs and feet. In some cases, the first sign of the disorder is sudden cardiac death. The severity of the condition varies among affected individuals, even in members of the same family.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Waddling gait
MedGen UID:
66667
Concept ID:
C0231712
Finding
Weakness of the hip girdle and upper thigh muscles, for instance in myopathies, leads to an instability of the pelvis on standing and walking. If the muscles extending the hip joint are affected, the posture in that joint becomes flexed and lumbar lordosis increases. The patients usually have difficulties standing up from a sitting position. Due to weakness in the gluteus medius muscle, the hip on the side of the swinging leg drops with each step (referred to as Trendelenburg sign). The gait appears waddling. The patients frequently attempt to counteract the dropping of the hip on the swinging side by bending the trunk towards the side which is in the stance phase (in the German language literature this is referred to as Duchenne sign). Similar gait patterns can be caused by orthopedic conditions when the origin and the insertion site of the gluteus medius muscle are closer to each other than normal, for instance due to a posttraumatic elevation of the trochanter or pseudarthrosis of the femoral neck.
Delayed speech and language development
MedGen UID:
105318
Concept ID:
C0454644
Finding
A degree of language development that is significantly below the norm for a child of a specified age.
Poor speech
MedGen UID:
341172
Concept ID:
C1848207
Finding
Motor delay
MedGen UID:
381392
Concept ID:
C1854301
Finding
A type of Developmental delay characterized by a delay in acquiring motor skills.
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.
Myopathy
MedGen UID:
10135
Concept ID:
C0026848
Disease or Syndrome
A disorder of muscle unrelated to impairment of innervation or neuromuscular junction.
Muscular dystrophy
MedGen UID:
44527
Concept ID:
C0026850
Disease or Syndrome
The term dystrophy means abnormal growth. However, muscular dystrophy is used to describe primary myopathies with a genetic basis and a progressive course characterized by progressive skeletal muscle weakness and wasting, defects in muscle proteins, and histological features of muscle fiber degeneration (necrosis) and regeneration. If possible, it is preferred to use other HPO terms to describe the precise phenotypic abnormalities.
Muscle weakness
MedGen UID:
57735
Concept ID:
C0151786
Finding
Reduced strength of muscles.
Gowers sign
MedGen UID:
65865
Concept ID:
C0234182
Finding
A phenomenon whereby patients are not able to stand up without the use of the hands owing to weakness of the proximal muscles of the lower limbs.
Facial palsy
MedGen UID:
87660
Concept ID:
C0376175
Disease or Syndrome
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.
Generalized hypotonia
MedGen UID:
346841
Concept ID:
C1858120
Finding
Generalized muscular hypotonia (abnormally low muscle tone).
Increased endomysial connective tissue
MedGen UID:
867771
Concept ID:
C4022161
Finding
An increased volume of the endomysium, which is a connective tissue sheath that surrounds each muscule fiber. Together, bundles of muscle fibers form a fasciculus, surrounded by another layer of connective tissue called the perimysium.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Elevated circulating creatine kinase concentration
MedGen UID:
69128
Concept ID:
C0241005
Finding
An elevation of the level of the enzyme creatine kinase (also known as creatine phosphokinase (CK; EC 2.7.3.2) in the blood. CK levels can be elevated in a number of clinical disorders such as myocardial infarction, rhabdomyolysis, and muscular dystrophy.
Ichthyosis
MedGen UID:
7002
Concept ID:
C0020757
Disease or Syndrome
An abnormality of the skin characterized the presence of excessive amounts of dry surface scales on the skin resulting from an abnormality of keratinization.
Mitochondrial hypertrophy
MedGen UID:
1740956
Concept ID:
C5435767
Finding
Enlargement of mitochondria. Mitochondrial hypertrophy is not discernible by light microscopy. By electron microscopy (EM), hypertrophic mitochondria have normal cristae and normal matrix density. In contrast, swollen mitochondria display swollen cristae and irregular matrix densities in EM.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVMegaconial type congenital muscular dystrophy
Follow this link to review classifications for Megaconial type congenital muscular dystrophy in Orphanet.

Recent clinical studies

Diagnosis

Zemorshidi F, Nafissi S, Boostani R, Karimiani EG, Ashtiani BH, Karimzadeh P, Miryounesi M, Tonekaboni SH, Nilipour Y
Neuromuscul Disord 2023 Jul;33(7):589-595. Epub 2023 Jun 19 doi: 10.1016/j.nmd.2023.06.006. PMID: 37393748
Wu T, Zhang C, He F, Yang L, Yin F, Peng J
Mol Genet Genomic Med 2023 Jul;11(7):e2162. Epub 2023 Mar 10 doi: 10.1002/mgg3.2162. PMID: 36896673Free PMC Article
Chan SH, Ho RS, Khong PL, Chung BH, Tsang MH, Yu MH, Yeung MC, Chan AO, Fung CW
Neuromuscul Disord 2020 Jan;30(1):47-53. Epub 2019 Nov 5 doi: 10.1016/j.nmd.2019.10.009. PMID: 31926838
Brady L, Giri M, Provias J, Hoffman E, Tarnopolsky M
Neuromuscul Disord 2016 Feb;26(2):160-4. Epub 2015 Dec 4 doi: 10.1016/j.nmd.2015.11.002. PMID: 26782016

Clinical prediction guides

Wu T, Zhang C, He F, Yang L, Yin F, Peng J
Mol Genet Genomic Med 2023 Jul;11(7):e2162. Epub 2023 Mar 10 doi: 10.1002/mgg3.2162. PMID: 36896673Free PMC Article

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