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Y-linked inheritance

Y-linked inheritance Overview Y-linked inheritance, or holandric inheritance, refers to the transmission of genes located exclusively on the Y chromosome. Because only males (XY) possess a Y chromosome, Y-linked traits are passed directly from father to son and cannot be inherited by females. This means all sons of an affected father will display the trait. Symptoms Y Chromosome Infertility: The most common symptom, often characterized by low sperm count (oligospermia) or no sperm production (azoospermia). Hypertrichosis of the Ears: Marked by the growth of long, dark hair on the outer rim of the ear. Webbed Toes: A condition where a web-like connection exists between the second and third toes. Porcupine Man: A rare condition characterized by skin that becomes dark, scaly, rough, and thick with bristle-like outgrowths. 47,XYY Syndrome: A chromosomal condition that can cause increased growth velocity, taller stature, delayed speech/language skills, and sometimes learning disabiliti...
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BAP1 tumor predisposition syndrome (BAP1-TPDS)

BAP1 tumor predisposition syndrome (BAP1-TPDS) Overview BAP1 tumor predisposition syndrome, also known as BAP1-TPDS or COMMON syndrome, is an inherited genetic disorder that may increase the risk of certain types of tumors, both cancerous and noncancerous. Symptoms Because BAP1-TPDS is hereditary and may be silent for a while, you may not experience symptoms or feel any differently. However, uveal melanoma, which is the most common cancer associated with BAP1-TPDS, may cause the following symptoms: Floaters or dark spots in the eye Blurred vision Headaches Unexpected flashes of light in the field of vision Other cancers associated with BAP1-TPDS include cutaneous melanoma, mesothelioma and clear cell renal cell carcinoma.   Cutaneous melanoma symptoms may include: Mole or spot on the skin that changes in shape, texture, color or size Bleeding, redness, swelling or a lump appearing in a mole Skin itching, pain or discomfort Skin sores that don’t seem to heal over time Mesothelioma a...
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Maternally Inherited Diabetes and Deafness (MIDD)

Maternally Inherited Diabetes and Deafness (MIDD)   Overview Maternally Inherited Diabetes and Deafness (MIDD) is a rare form of maternally inherited diabetes (roughly 1% of cases) caused by mitochondrial DNA mutations, most commonly \(m.3243A>G\). It causes high blood sugar and sensorineural hearing loss, typically emerging in mid-adulthood, along with potential macular retinal dystrophy and muscle issues. Symptoms Diabetes Mellitus (∼85% of cases): Onset: Typically in the 30s or 40s (ranging from childhood to late adulthood). Characteristics: Non-obese, low or normal BMI, often misdiagnosed as Type 1 or Type 2 diabetes. Progression: Initially may be diet-controlled or treated with oral medications, but often progresses to insulin deficiency. Sensorineural Hearing Loss (∼75% of cases): Nature: Gradual, high-frequency hearing loss that usually affects both ears (sensorineural). Timing: Often precedes the onset of diabetes. Severity: More severe and faster progression in men t...
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Yellow Nail Syndrome

Yellow Nail Syndrome Overview What is yellow nail syndrome? Yellow nail syndrome is a rare condition that affects your nails, lungs and limbs. People with yellow nail syndrome get yellow, curved nails that may thicken or fall off. They also may have respiratory symptoms, such as a chronic cough, and usually have swollen lower legs or ankles. Experts don’t know what causes yellow nail syndrome. But it may be linked to improper circulation, issues with lymphatic drainage or buildup of fluid around your lungs. You may also have a higher risk if you have one of a few specific chronic diseases, dental implants or a joint replacement. Who might get yellow nail syndrome? Yellow nail syndrome develops most often in adults over 50. More rarely, yellow nail syndrome sometimes occurs in children. Some reports show higher rates of yellow nail syndrome in people with: Autoimmune diseases. Cancer. Nephrotic syndrome. Rheumatoid arthritis (RA). Thyroid disease. Symptoms What are the symptoms of yello...
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Progressive myoclonic epilepsy type 1

Progressive myoclonic epilepsy type 1  Overview Progressive myoclonic epilepsy type 1 (EPM1 or Unverricht-Lundborg disease) is a rare autosomal recessive neurodegenerative disorder, often considered the most common progressive myoclonic epilepsy, characterized by stimulus-sensitive myoclonus and seizures starting between ages 6–16. Caused by mutations in the CSTB gene, it features progressive worsening of muscle jerks, ataxia, and mild cognitive decline, with treatment focusing on managing symptoms through medication. Symptoms Action Myoclonus: The hallmark symptom, featuring involuntary muscle jerks triggered by movement, light, or stress, often leading to disability. Seizures: Generalized tonic-clonic seizures are common, usually appearing early but often responding to medication. Progressive Neurological Decline: Symptoms worsen over time, including ataxia (lack of coordination), intentional tremors, and dysarthria. Age of Onset: Symptoms generally begin between 6 and 15 yea...
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Xeroderma Pigmentosum (XP)

Xeroderma Pigmentosum (XP) Overview Xeroderma pigmentosum (XP) is a rare genetic disorder that causes hypersensitivity to ultraviolet (UV) light. Symptoms usually affect the parts of your body that are regularly exposed to the sun, such as your face, arms and lips. People with XP usually start showing symptoms in early childhood. They may get blistering sunburns after even just a few minutes in the sun. How does xeroderma pigmentosum affect my body? People with XP develop sunburns easily and have a higher risk of skin cancer. Compared to those with average risk, people with XP have: 10,000 times higher risk of developing nonmelanoma skin cancer, such as basal cell carcinoma or squamous cell carcinoma. 2,000 times higher risk of developing melanoma. Some reports have also found that people with XP are more likely to develop cancers such as: Astrocytoma. Breast cancer. Glioblastoma. Kidney cancer. Leukemia. Lung cancer. Pancreatic cancer. Stomach cancer. Testicular cancer. Thyroid cancer...
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Bosma Arhinia Microphthalmia Syndrome

Bosma Arhinia Microphthalmia Syndrome Overview Bosma arhinia microphthalmia (BAM) syndrome is an extremely rare genetic disorder defined by three major features: 1) complete absence of the nose (arhinia) 2) eye abnormalities and 3) lack of typical sexual development during puberty (absent sexual maturation).   The specific symptoms and severity of the disorder can vary from one person to another. For example, eye problems can range from absent tear ducts (the small tubes that carry tears from the eyes to the nose) to very small eyes and/or blindness.   In males, BAM syndrome may cause underdeveloped genitalia at birth, including a small penis and/or testes that do not descend properly into the scrotum. In females, reproductive differences are usually not noticeable until adolescence when she does not develop breasts or have menstrual periods.   The only known genetic cause of BAM syndrome is a change (variant) in the SMCHD1 gene. In most cases, this genetic...
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