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Primary Familial Brain Calcification

Primary Familial Brain Calcification Overview Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder characterized by the presence of abnormal calcium/hydroxyapatite deposits (calcifications) in the brain. The clinical presentations generally attributed to these brain calcifications are highly heterogeneous, ranging from asymptomatic patients to severe cases with progressive neuropsychiatric features. To date, disease-causing changes (pathogenic variants or mutations) in six genes have been associated with PFBC: SLC20A2, PDGFB, PDGFRB, XPR1, MYORG and JAM-2. PFBC has recently become the preferred name for this condition because variants in specific genes are now known to be the cause of the condition. Previously, familial idiopathic basal ganglia calcification was the preferred name, and Fahr’s disease is often used for either familial or sporadic brain calcification, and it is unknown if these are the same or different diseases. Symptoms PFBC is characterized...
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Holocarboxylase synthetase deficiency (HLCSD)

Holocarboxylase synthetase deficiency (HLCSD) Overview Holocarboxylase synthetase deficiency (HLCSD) is a rare, inherited metabolic disorder in which the body cannot use vitamin B7 (biotin) effectively, leading to a condition known as multiple carboxylase deficiency. Classified as a multiple carboxylase deficiency, the condition impairs the activity of biotin-dependent enzymes (carboxylases) needed to process proteins, fats, and carbohydrates. Symptoms Symptoms typically begin in infancy—often within the first few weeks or months of life—though onset can occasionally vary. • Feeding & Digestive Issues: Difficulty feeding, poor appetite, vomiting (emesis), and food refusal. • Skin & Hair Changes: Distinctive skin rashes (dermatitis/peeling rash) and hair loss (alopecia). • Neurological & Muscular Signs: Lethargy or extreme tiredness, low muscle tone (hypotonia), irritability, developmental delay, and seizures (convulsions). • Respiratory Problems: Rapid breathing (tachypn...
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Burn-McKeown syndrome

Burn-McKeown syndrome Overview Burn-McKeown syndrome is a rare, congenital genetic disorder characterized by nasal passage blockages, distinctive facial features, hearing loss, and heart or growth abnormalities, while generally leaving intelligence unaffected Symptoms • Nasal Passage Abnormalities: • Bilateral choanal stenosis (narrowing) or bilateral choanal atresia (complete blockage of the nasal passages), which can lead to life-threatening breathing and respiratory distress issues in newborns if not surgically repaired. • Craniofacial (Facial) Features: • Short palpebral fissures: Narrow openings of the eyelids, sometimes accompanied by downslanting. • Coloboma: A gap or defect in the lower eyelids, often with eyelashes present medial to the defect. • Hypertelorism: Widely spaced eyes. • Prominent nasal bridge: A high or prominent bridge of the nose. • Philtrum abnormalities: A short space between the nose and the upper lip. • Mouth and lips: A small opening of the mou...
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Tetrahydrobiopterin Deficiency

Tetrahydrobiopterin Deficiency Overview Tetrahydrobiopterin (BH4) deficiencies is a general term for a group of disorders characterized by abnormalities in the creation (biosynthesis) or regeneration of tetrahydrobiopterin, a naturally occurring compound that acts as a cofactor. A cofactor is a non-protein substance in the body that enhances or is necessary for the proper function of certain enzymes. When tetrahydrobiopterin is deficient, the chemical balance within the body is upset. In most of these disorders, there are abnormally high levels of the amino acid phenylalanine (hyperphenylalaninemia). Amino acids such as phenylalanine are chemical building blocks of proteins and are essential for proper growth and development. Most of these disorders also cause abnormally low levels of neurotransmitters. Neurotransmitters are chemicals that modify, amplify or transmit nerve impulses from one nerve cell to another, enabling nerve cells to communicate. These chemical imbalances can ultima...
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Sitosterolemia

Sitosterolemia Overview Sitosterolemia is a rare genetic condition that causes the body to store plant sterols. There are at least two types of sterols: sterols from animals (example, cholesterol) and sterols from plants –also called phytosterols (example, sitosterol). Most people normally absorb plant sterols from the food they eat and excrete them in the gut. People with sitosterolemia absorb plant sterols but cannot excrete them, resulting in the accumulation of plant sterols in the body, especially in the blood and the arteries. Sitosterolemia is an autosomal recessive genetic condition caused by changes (mutations) in the ABCG5 or ABCG8 gene. Standard lipid profiles do not check for plant sterol in the blood, so sitosterolemia is frequently missed unless a special blood test is ordered. Variability in presenting signs and symptoms and low awareness of this condition contribute to missed or delayed diagnosis. If left untreated, sitosterolemia can lead to premature hardening of the ...
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Beta-ureidopropionase deficiency

Beta-ureidopropionase deficiency Overview Beta-ureidopropionase deficiency is a very rare inherited metabolic disorder that affects how the body breaks down pyrimidines (the building blocks of DNA and RNA). Symptoms • Neurological & Developmental: • Hypotonia: Low muscle tone or "floppy" muscle strength. • Seizures / Epilepsy : Recurrent or unprovoked convulsive episodes. • Developmental Delay : Lying, sitting, walking, or reaching milestones later than expected. • Intellectual Disability: Ranging from mild to more pronounced cognitive impairment. • Speech Difficulties: Delayed language acquisition or articulation issues. • Autistic Behaviors: Challenges affecting social interaction and communication. • Physical & Structural: • Microcephaly : An abnormally small head size in some individuals. • Brain Abnormalities: Structural variations visible on medical imaging (such as an MRI). • Optic Nerve Deterioration: Atrophy leading to potential vision loss. • Asymptomati...
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Nijmegen breakage syndrome (NBS)

Nijmegen breakage syndrome (NBS) Overview Nijmegen breakage syndrome (NBS) is a rare autosomal recessive genetic disorder caused by mutations in the NBN gene (located on chromosome 8q21), which encodes a protein called nibrin. This defect impairs the body's ability to repair double-strand breaks in DNA, leading to chromosomal instability, heightened sensitivity to radiation, and cell damage Symptoms • Microcephaly : A small head circumference that is usually present at birth or becomes noticeable within the first few months and progressively slows down relative to body growth. • Distinctive Facial Features: A sloping forehead, prominent midface/nose, receding lower jaw (mandible), large ears, and sparse hair. • Growth and Developmental Delays: Mild growth restriction leading to short stature, alongside normal early intellectual development followed by mild-to-moderate intellectual disability or learning delays. • Recurrent Infections: Frequent and severe respiratory tract infecti...
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