Condition Lookup
Sub-Category:
X-Linked Disorders
Number of Conditions: 6
Duchenne muscular dystrophy (DMD gene mutation)
Specialty: Genetics
Category: Single-Gene Disorders (Mendelian Inheritance)
Sub-category: X-Linked Disorders
Symptoms:
progressive muscle weakness; delayed motor milestones; difficulty climbing stairs; waddling gait; calf pseudohypertrophy; respiratory complications; cardiomyopathy
Root Cause:
Mutations in the DMD gene lead to the absence or deficiency of dystrophin, a protein essential for muscle integrity.
How it's Diagnosed: videos
Clinical evaluation, elevated creatine kinase (CK) levels, genetic testing for DMD mutations, muscle biopsy (rarely used).
Treatment:
Physical therapy, corticosteroids, assistive devices, multidisciplinary care (including cardiology and respiratory specialists).
Medications:
Prednisone or deflazacort (corticosteroids) to slow muscle degeneration; exon-skipping drugs like eteplirsen for specific mutations.
Prevalence:
How common the health condition is within a specific population.
Affects approximately 1 in 3,500 to 5,000 male births worldwide.
Risk Factors:
Factors or behaviors that increase the likelihood of developing the condition.
Family history of DMD mutations; primarily affects males due to X-linked inheritance.
Prognosis:
The expected outcome or course of the condition over time.
Progressive and life-limiting; survival often into the 20s or 30s with advanced care.
Complications:
Additional problems or conditions that may arise as a result of the original condition.
Respiratory failure, heart failure, scoliosis, contractures, and reduced mobility.
Hemophilia A (F8 gene mutation)
Specialty: Genetics
Category: Single-Gene Disorders (Mendelian Inheritance)
Sub-category: X-Linked Disorders
Symptoms:
spontaneous bleeding; prolonged bleeding after injuries or surgeries; joint swelling and pain; easy bruising
Root Cause:
Mutations in the F8 gene lead to deficiency or dysfunction of clotting factor VIII, impairing blood clotting.
How it's Diagnosed: videos
Coagulation tests (prolonged activated partial thromboplastin time), factor VIII activity assays, genetic testing.
Treatment:
Regular infusion of recombinant or plasma-derived factor VIII concentrates; prophylactic therapy to prevent bleeding episodes.
Medications:
Emicizumab (monoclonal antibody for prophylaxis), desmopressin (for mild cases), clotting factor concentrates (recombinant or plasma-derived).
Prevalence:
How common the health condition is within a specific population.
Affects approximately 1 in 5,000 male births worldwide.
Risk Factors:
Factors or behaviors that increase the likelihood of developing the condition.
Family history of hemophilia A; primarily affects males due to X-linked inheritance.
Prognosis:
The expected outcome or course of the condition over time.
With appropriate treatment, individuals can lead relatively normal lives; untreated, can result in severe disability or death.
Complications:
Additional problems or conditions that may arise as a result of the original condition.
Joint damage from repeated bleeding, inhibitor formation (antibodies to factor VIII), intracranial hemorrhage.
Hemophilia B (F9 gene mutation)
Specialty: Genetics
Category: Single-Gene Disorders (Mendelian Inheritance)
Sub-category: X-Linked Disorders
Symptoms:
spontaneous bleeding; prolonged bleeding after injuries or surgeries; joint swelling and pain; easy bruising
Root Cause:
Mutations in the F9 gene lead to deficiency or dysfunction of clotting factor IX, impairing blood clotting.
How it's Diagnosed: videos
Coagulation tests (prolonged activated partial thromboplastin time), factor IX activity assays, genetic testing.
Treatment:
Regular infusion of recombinant or plasma-derived factor IX concentrates; prophylactic therapy to prevent bleeding episodes.
Medications:
Factor IX concentrates (recombinant or plasma-derived), non-factor therapies (emerging treatments).
Prevalence:
How common the health condition is within a specific population.
Affects approximately 1 in 25,000 male births worldwide.
Risk Factors:
Factors or behaviors that increase the likelihood of developing the condition.
Family history of hemophilia B; primarily affects males due to X-linked inheritance.
Prognosis:
The expected outcome or course of the condition over time.
With treatment, individuals can lead a normal life; untreated, can result in severe disability or death.
Complications:
Additional problems or conditions that may arise as a result of the original condition.
Joint damage from repeated bleeding, inhibitor formation (antibodies to factor IX), intracranial hemorrhage.
Fragile X syndrome (FMR1 gene mutation)
Specialty: Genetics
Category: Single-Gene Disorders (Mendelian Inheritance)
Sub-category: X-Linked Disorders
Symptoms:
intellectual disability; behavioral challenges; anxiety; hyperactivity; autistic traits; long face; large ears; macroorchidism in males
Root Cause:
Expansion of CGG repeats in the FMR1 gene leads to loss of function of FMRP protein, essential for neural development.
How it's Diagnosed: videos
Genetic testing to identify CGG repeat expansions in the FMR1 gene.
Treatment:
Supportive therapies, including special education, behavioral therapy, speech therapy, and medication for symptoms like anxiety or hyperactivity.
Medications:
Stimulants (e.g., methylphenidate ) for ADHD symptoms, selective serotonin reuptake inhibitors (SSRIs) for anxiety.
Prevalence:
How common the health condition is within a specific population.
Affects approximately 1 in 4,000 males and 1 in 8,000 females worldwide.
Risk Factors:
Factors or behaviors that increase the likelihood of developing the condition.
Family history of FMR1 mutations; primarily affects males, though females can have milder symptoms.
Prognosis:
The expected outcome or course of the condition over time.
Variable; with support, individuals can achieve meaningful developmental milestones.
Complications:
Additional problems or conditions that may arise as a result of the original condition.
Learning difficulties, social challenges, and physical symptoms persist throughout life.
Rett syndrome (MECP2 gene mutation)
Specialty: Genetics
Category: Single-Gene Disorders (Mendelian Inheritance)
Sub-category: X-Linked Disorders
Symptoms:
loss of acquired skills; hand-wringing movements; breathing irregularities; seizures; developmental regression; motor impairments
Root Cause:
Mutations in the MECP2 gene impair regulation of gene expression, critical for brain development.
How it's Diagnosed: videos
Clinical evaluation of developmental history and genetic testing for MECP2 mutations.
Treatment:
Symptom management through therapies (physical, occupational, speech), anticonvulsants, and supportive care.
Medications:
Antiepileptic drugs (e.g., valproate, levetiracetam ) for seizures; medications for spasticity or anxiety as needed.
Prevalence:
How common the health condition is within a specific population.
Affects approximately 1 in 10,000 to 15,000 females; rare in males.
Risk Factors:
Factors or behaviors that increase the likelihood of developing the condition.
De novo mutations in MECP2; no significant familial risk in most cases.
Prognosis:
The expected outcome or course of the condition over time.
Life-long challenges; early intervention improves quality of life, but no cure exists.
Complications:
Additional problems or conditions that may arise as a result of the original condition.
Seizures, scoliosis, breathing difficulties, nutritional challenges.
X-linked adrenoleukodystrophy (ABCD1 gene mutation)
Specialty: Genetics
Category: Single-Gene Disorders (Mendelian Inheritance)
Sub-category: X-Linked Disorders
Symptoms:
behavioral changes; progressive neurological decline; adrenal insufficiency; spasticity; vision and hearing loss
Root Cause:
Mutations in the ABCD1 gene impair peroxisomal beta-oxidation, leading to accumulation of very long-chain fatty acids (VLCFAs) in tissues.
How it's Diagnosed: videos
Elevated VLCFA levels in plasma, genetic testing for ABCD1 mutations, MRI for brain changes.
Treatment:
Adrenal hormone replacement, hematopoietic stem cell transplantation (HSCT) in early stages, supportive care.
Medications:
Corticosteroids (e.g., hydrocortisone ) for adrenal insufficiency; investigational therapies for VLCFA reduction.
Prevalence:
How common the health condition is within a specific population.
Affects approximately 1 in 20,000 males worldwide.
Risk Factors:
Factors or behaviors that increase the likelihood of developing the condition.
Family history of ABCD1 mutations; primarily affects males.
Prognosis:
The expected outcome or course of the condition over time.
Progressive and potentially fatal; early detection and treatment can improve outcomes.
Complications:
Additional problems or conditions that may arise as a result of the original condition.
Adrenal crisis, severe neurological disability, early death without intervention.