# Alström Syndrome Glossary
Every term used across this site, defined in plain language. Each entry includes the term, an everyday explanation, and where to learn more.
For pages on this site referenced below, use the linked URLs. For complex pronunciations, the phonetic guide in brackets — e.g., [eye-EYE-uh-tuhl] — is read like English syllables.
A
Acanthosis nigricans [a-can-THO-sis NYE-grih-cans] — Dark, velvety patches of skin, usually in folds (neck, armpits, groin), that signal high insulin levels. Common in Alström. Not dirt — they don't wash off. → Read more
ACE inhibitor — A type of heart medication (like enalapril or lisinopril) that helps the heart work more easily and protects against heart-failure progression. Often used in Alström-related cardiomyopathy. → Read more
Adolescence — The teen years, typically ages 13–18. Often the most challenging period in Alström because of accelerated vision loss, diabetes onset, and identity formation. → Read more
ALMS1 — The gene that causes Alström Syndrome when both copies are altered. Located on chromosome 2. Codes for a large protein that lives in primary cilia. → Read more
ALMS — Short for Alström Syndrome. Sometimes used as the abbreviation in medical records.
Alström Syndrome International (ASI) — The largest global Alström patient organization, headquartered in the US, supporting families in 47 countries. Operates the world's largest Alström clinical database. → Visit ASI
Alström Syndrome UK (ASUK) — UK-based Alström patient organization that works closely with the NHS Highly Specialised Service. → Visit ASUK
Amniocentesis [am-nee-oh-sen-TEE-sis] — A prenatal test where a small amount of amniotic fluid is taken to check the baby's genes. Usually done from 15 weeks of pregnancy. → Read more
Anesthesiologist — The doctor who manages anesthesia (sleep medicine) during surgery. Important to brief about Alström-related cardiac and metabolic issues before any procedure.
Antisense oligonucleotide (ASO) — A type of drug that binds to RNA to change how a gene is processed. Being researched for some Alström variants.
Audiogram — The chart produced by a hearing test that shows what sounds you can hear at different pitches and volumes. → Read more
Audiologist — The professional who tests hearing and fits hearing aids. → Read more
Auditory brainstem response (ABR) — A hearing test that measures the brain's response to sounds. Used in babies and young children who can't cooperate with regular testing.
Autosomal recessive — An inheritance pattern where you need two altered copies of a gene (one from each parent) to have a condition. Both parents are carriers but don't have the condition themselves. → Read more
B
Basal body — The structure at the base of a primary cilium. The ALMS1 protein lives here. → Read more
Bardet-Biedl Syndrome (BBS) — Another ciliopathy that shares some features with Alström but is caused by different genes. Includes polydactyly (extra fingers/toes), which Alström doesn't. → Read more
Beta-blocker — A heart medication (like carvedilol or metoprolol) that slows heart rate and protects heart muscle. Often used in Alström cardiomyopathy. → Read more
BiPAP — Two-pressure positive airway pressure. A type of breathing support similar to CPAP, but with two pressure levels. Used for some patients with sleep-related breathing issues.
BNP / NT-proBNP — Blood tests that measure heart-failure markers. High levels suggest the heart is under strain.
Brachydactyly [brak-ee-DACK-tih-lee] — Short fingers or toes. A common but usually harmless feature of Alström.
Braille — The tactile reading system using raised dots. Most experts recommend introducing Braille to children with progressive vision loss before vision is fully gone, typically between ages 4 and 7. → Read more
C
Cardiologist — The doctor who specializes in the heart. Essential team member for everyone with Alström.
Cardiomyopathy [car-dee-oh-my-OPP-uh-thee] — Disease of the heart muscle. In Alström, this is usually dilated cardiomyopathy in infancy and sometimes restrictive cardiomyopathy in adulthood. → Read more
Carrier — A person with one altered copy of a recessive gene. Carriers don't have the condition themselves but can pass the altered copy to their children. → Read more
Centrosome — A structure inside cells that helps organize cell division. ALMS1 protein is found here as well as in cilia.
Chorionic villus sampling (CVS) — A prenatal test where a small sample of placental tissue is taken to test the baby's genes. Usually done at 10–13 weeks of pregnancy. → Read more
Chromosome — Structures in cells that contain DNA. Humans have 23 pairs. The ALMS1 gene is on chromosome 2.
Cilia [SILL-ee-uh] (singular: cilium) — Tiny antenna-like structures on cells that sense signals from the environment. ALMS1 is essential for cilia to work. → Read more
Ciliopathy [silly-OPP-uh-thee] — A disease caused by problems with cilia. Alström and Bardet-Biedl are both ciliopathies.
Cirrhosis [sih-ROH-sis] — Severe scarring of the liver. End-stage liver disease in Alström can include cirrhosis. → Read more
Cochlea [COKE-lee-uh] — The inner-ear structure responsible for hearing. Hearing loss in Alström originates here.
Cochlear implant — A surgically-placed device that bypasses the cochlea and stimulates the auditory nerve directly. An option for severe hearing loss. → Read more
Compassionate Allowances — A US Social Security Administration program that expedites disability applications for severe medical conditions. Alström qualifies. → Read more
Compound heterozygote — A person with two different altered copies of the same gene. Most people with Alström are compound heterozygotes — they have one variant from each parent, and the variants are different.
Cone-rod dystrophy — The eye condition that causes vision loss in Alström. Cones (handle bright light, color, detail) fail first; rods (handle dim light, peripheral vision) follow. → Read more
Cones — One of two types of photoreceptors in the eye. Handle bright light, color, and central vision. Affected first in Alström.
CPAP — Continuous positive airway pressure. A machine that gently pushes air through a mask during sleep, keeping the airway open. Standard treatment for sleep apnea. → Read more
CGM (continuous glucose monitor) — A small wearable sensor that measures blood glucose continuously and sends data to a phone. Particularly useful for managing diabetes when vision is reduced.
CKD (chronic kidney disease) — Long-term reduction in kidney function. Common in adults with Alström. → Read more
D
Deafblindness — Combined hearing and vision loss. Most adults with Alström experience some degree of deafblindness.
Detrusor-urethral dyssynergia — A bladder condition where the bladder muscle and the urethral sphincter don't coordinate properly during urination. Common in Alström, particularly in adult women. → Read more
Dialysis — Treatment that filters the blood when kidneys can no longer do so. Two main types: hemodialysis (at a center) and peritoneal dialysis (at home). → Read more
Diastolic — Relating to the relaxation phase of the heart. Restrictive cardiomyopathy primarily affects diastolic function (the heart can't fill properly).
Dilated cardiomyopathy (DCM) — Heart muscle is weakened and chambers are enlarged. The most common heart condition in Alström infants.
E
Echocardiogram [eck-oh-CARD-ee-oh-gram] — Ultrasound of the heart. Standard test for checking heart structure and function. → Read more
Education Health and Care Plan (EHCP) — UK educational plan for children with significant special educational needs. Equivalent to the US IEP.
eGFR (estimated glomerular filtration rate) — A blood-test-based measure of kidney function. Lower numbers indicate worse kidney function.
EKG / ECG — Electrocardiogram. A recording of the heart's electrical activity. Standard part of cardiac monitoring.
Endocrinologist — The doctor who manages hormones, diabetes, and metabolism. Essential team member in Alström.
Endometrial — Relating to the lining of the uterus. Women with PCOS and irregular periods need attention to endometrial health.
Enzyme — A protein that speeds up specific chemical reactions in the body. Some Alström features relate to enzyme function.
ERG (electroretinogram) [ee-lek-troh-RET-in-oh-gram] — A test of the eye's electrical response to light. The most useful test for diagnosing cone-rod dystrophy. → Read more
Esophageal varices [eh-SOFF-uh-jee-uhl VAIR-ih-seez] — Enlarged veins in the esophagus. A complication of advanced liver disease that requires medical surveillance.
Exon — The protein-coding part of a gene. ALMS1 has 23 exons. Most Alström-causing variants are in exons 8, 10, and 16.
Exome — The collection of all exons in a person's DNA. Whole-exome sequencing tests them all.
F
FAQPage schema — Structured data on a webpage that tells search engines about FAQ content. Important for ranking in search.
Fasting glucose — Blood sugar measured after not eating for 8+ hours. A standard diabetes screening test.
Fasting insulin — Insulin level measured after not eating. High in Alström even before diabetes appears, reflecting severe insulin resistance.
Fibrates — A class of medications used to lower triglycerides. Sometimes needed in Alström.
Fibrosis — Scarring of tissue. Can develop in liver, lung, kidney, and heart in Alström over time.
Fovea [FOH-vee-uh] — The central part of the retina with the highest density of cones. Critical for sharp central vision.
Frameshift mutation — A genetic change that shifts how the cell reads the gene, scrambling the resulting protein. Common in Alström.
Fundus examination — Looking at the back of the eye through a dilated pupil. Standard ophthalmology check.
G
GARD (Genetic and Rare Diseases Information Center) — NIH-run information resource for rare diseases. Lists Alström. → Visit GARD
Gene — A unit of inheritance — a stretch of DNA that codes for one protein.
GeneReviews — A peer-reviewed online resource describing genetic conditions for clinicians and families. The GeneReviews chapter on Alström is the most authoritative single clinical reference. → Visit GeneReviews on Alström
Genetic counselor — A professional trained in genetics and counseling who helps families understand genetic test results, inheritance, and family-planning options. → Read more
Genetic testing — Lab analysis of DNA to identify variants. For Alström, looks for changes in the ALMS1 gene.
Geneticist — A medical doctor who specializes in genetic conditions. Often the diagnostician for Alström.
Genotype — The specific genetic makeup of a person — the actual sequence of DNA they have.
Gingivitis — Gum inflammation. Can occur in Alström, often along with other dental findings.
GLP-1 agonist — A class of diabetes medications (like semaglutide, liraglutide) that help control blood sugar, support weight loss, and protect the cardiovascular system.
Glomerulus [gloh-MARE-yoo-lus] — The filtering unit of the kidney. Glomerular damage drives kidney disease in Alström.
Glucose — Blood sugar. The body's main fuel.
Growth hormone (GH) — A hormone that supports normal growth. Some patients with Alström have reduced GH function.
H
HbA1c (hemoglobin A1c) — A blood test that reflects average blood sugar over 2–3 months. Standard for diabetes monitoring.
Hemodialysis — Dialysis using a machine outside the body, typically 3 times per week at a dialysis center.
Hepatology — The branch of medicine that focuses on the liver.
Hepatomegaly — Enlarged liver. Sometimes seen in Alström related to NAFLD.
Heterozygous — Having one altered copy of a gene and one normal copy. A carrier is heterozygous.
Highly Specialised Service (HSS) — UK NHS-funded specialist service for rare conditions. The Alström service is at Birmingham. → Read more
Hirsutism — Excess hair growth on the face, chest, abdomen, or back, in a male pattern. Common in women with PCOS, including women with Alström.
Holter monitor — A wearable EKG that records heart rhythm over 24 hours or longer. Used to detect intermittent arrhythmias.
Homozygous — Having two identical copies of a gene. People with Alström from consanguineous families may be homozygous for the same ALMS1 variant.
Hypertriglyceridemia [HY-per-try-glih-sih-RIDE-ee-mee-uh] — High blood triglycerides. Common in Alström because of severe insulin resistance. → Read more
Hypogonadism [HY-poh-GO-nuh-dizm] — Reduced function of the gonads (testes or ovaries). Common in adults with Alström. → Read more
Hypothalamus — Part of the brain that regulates many body functions including hunger, energy balance, and hormones. Affected in Alström, contributing to obesity.
Hypothyroidism — Underactive thyroid. Treatable with levothyroxine. → Read more
I
IEP (Individualized Education Program) — A US legal document outlining the special services and accommodations a student with disabilities will receive. → Read more
IGF-1 (insulin-like growth factor 1) — A hormone related to growth. Levels are checked when assessing growth-hormone function.
Implantable cardioverter-defibrillator (ICD) — A device implanted in the chest to detect and treat dangerous heart rhythms.
Inheritance — The pattern by which a genetic condition is passed from parents to children. Alström is autosomal recessive.
Insulin — A hormone that helps cells take up glucose from the blood. Severely affected in Alström.
Insulin pump — A small device that continuously delivers insulin through a small tube under the skin. Many adults with Alström use pumps.
Insulin resistance — When cells don't respond well to insulin's signal. Severe in Alström — among the most extreme described in medicine. → Read more
Intervener — A specially trained professional who provides one-on-one communication and learning support to a deafblind student. → Read more
Intron — Non-coding part of a gene between exons. Some Alström variants are in introns and can be missed by standard sequencing.
IVF (in vitro fertilization) — Conception outside the body. Used in combination with PGD when carrier couples want to test embryos.
J–K
JSON-LD — A structured data format used to tell search engines about page content. Important for SEO of medical pages.
Karyotype — A picture of all chromosomes. Standard genetic test that doesn't usually identify Alström — DNA-level testing of ALMS1 is needed.
Kidney transplant — Surgical placement of a healthy kidney to replace failing kidneys. → Read more
Kyphosis — Forward (rounded) curvature of the upper back. Common in Alström.
L
Leber Congenital Amaurosis (LCA) — A group of inherited retinal dystrophies that present in infancy. Sometimes the first diagnosis in babies with Alström before systemic features emerge.
Levothyroxine — Synthetic thyroid hormone. The standard treatment for hypothyroidism.
Light perception (LP) — The ability to detect light, even without seeing details. Some adults with Alström retain LP; others don't.
Lipemia retinalis — A milky appearance of retinal blood vessels caused by very high triglycerides. Rare but reported in Alström.
Lipid panel — Blood test that measures cholesterol, triglycerides, HDL, and LDL.
Low vision — Reduced vision that can't be corrected with glasses, contacts, or surgery. Most people with Alström have low vision before becoming functionally blind.
Low-vision specialist — Optometrist or ophthalmologist who fits magnifiers, tinted lenses, and other aids for people with reduced vision. → Read more
M
Medical home — A coordinated primary-care model for people with chronic conditions. Many children's hospitals offer medical homes for medically complex children.
Medicaid — US public health insurance. Often covers services for children with disabilities through specific programs and waivers.
MedicalWebPage — A schema.org type for medical content. Helps search engines understand and rank medical pages.
Medicare — US public health insurance for people 65+ and adults with long-term disability.
Metformin — A widely-used diabetes medication. Often first-line in Alström for managing insulin resistance and pre-diabetes.
Microalbuminuria — Small amounts of albumin in urine. An early sign of kidney damage; standard surveillance test.
Missense mutation — A genetic change that swaps one amino acid for another. Less common in Alström than nonsense or frameshift mutations.
Mitochondria — Cellular structures that produce energy. Sometimes part of the differential when babies have unexplained cardiomyopathy.
Molecular genetic analysis — DNA-level testing. Used to identify ALMS1 variants for diagnosing Alström.
Multidisciplinary clinic — A clinic where several specialists see patients together in coordinated visits. Standard for high-quality Alström care. → Read more
N
NAFLD (non-alcoholic fatty liver disease) — Fat accumulation in the liver not caused by alcohol. Nearly universal in adults with Alström. → Read more
NASH (non-alcoholic steatohepatitis) — A more severe form of NAFLD with inflammation. Can progress to fibrosis and cirrhosis.
Nephrologist — The kidney specialist.
Nephropathy — Kidney disease.
NHS (National Health Service) — The UK's public health system. Funds the Highly Specialised Service for Alström.
No light perception (NLP) — Total blindness without ability to detect light. Some adults with Alström reach NLP.
Nonsense mutation — A genetic change that turns a coding instruction into a "stop" instruction, producing a truncated, non-functional protein. Common in Alström.
NORD (National Organization for Rare Disorders) — US patient-advocacy organization for rare diseases. → Visit NORD
Nystagmus — Involuntary, repetitive eye movements. Common in babies with Alström. → Read more
O
OAE (otoacoustic emissions) — A hearing test that measures the response of the outer hair cells in the cochlea. Helpful in evaluating Alström-related hearing loss.
Obstructive sleep apnea (OSA) — Pauses in breathing during sleep due to airway closure. Common in Alström. → Read more
OCT (optical coherence tomography) — Imaging that shows cross-sections of the retinal layers. Useful for tracking cone-rod dystrophy progression. → Read more
OMIM (Online Mendelian Inheritance in Man) — A clinical-genetics encyclopedia. Alström's OMIM entry is #203800.
Ophthalmologist — Eye specialist (medical doctor).
Orientation and Mobility (O&M) — Skills for navigating environments safely and independently when blind or low-vision. Includes white cane training.
Orphanet — European reference resource for rare diseases. → Visit Orphanet
OSA — See Obstructive sleep apnea.
Otologist / otolaryngologist (ENT) — Specialist in ears, nose, and throat. Sometimes coordinates cochlear implants.
P
Pancreatitis — Inflammation of the pancreas. Severe risk with very high triglycerides; can be life-threatening.
Paratransit — Door-to-door public transportation for people with disabilities. Often subsidized.
Pathogenic variant — A genetic change known to cause disease.
PCOS (polycystic ovary syndrome) — A common condition in women that involves irregular cycles, increased androgens, and metabolic features. More common in women with Alström. → Read more
Pediatrician — Children's primary care doctor.
PGD (preimplantation genetic diagnosis) — Testing IVF embryos before transfer to identify those with or without genetic conditions. → Read more
Pharmaceutical assistance programs — Programs that help patients afford expensive medications. Run by drug manufacturers and patient organizations.
Phenotype — The observable features and symptoms of a person, in contrast to genotype.
Photophobia [FOH-toe-FOH-bee-uh] — Sensitivity or pain in response to light. Severe in Alström because of cone dysfunction. → Read more
Photoreceptor — Light-sensing cells in the retina. Cones and rods are types of photoreceptors.
Physical therapy (PT) — Therapy focused on movement, strength, and physical function.
Pioglitazone — A diabetes medication that addresses insulin resistance directly. Sometimes used in Alström.
Polydactyly — Extra fingers or toes. A feature of Bardet-Biedl Syndrome (not Alström).
Polysomnogram (PSG) — A sleep study that monitors brain waves, breathing, oxygen, heart rate, and movements during sleep. Used to diagnose sleep apnea.
Primary care provider (PCP) — Your or your child's main doctor. The "quarterback" of the care team.
Primary cilium — The single, antenna-like structure on most cells. ALMS1 protein lives at its base.
Pulmonary artery banding — A cardiac surgical procedure sometimes used in severe infant cardiomyopathy. → Read more
Pulmonary fibrosis — Scarring of the lungs. Can develop in adults with Alström.
Pulmonary hypertension — High blood pressure in the lungs' arteries. Can occur in Alström related to lung or cardiac disease.
Pulmonologist — Lung specialist.
Q–R
QTVI (Qualified Teacher of Children and Young People with Vision Impairment) — UK educational specialist for visually-impaired students. Equivalent to the US TVI.
Recessive — An inheritance pattern requiring two altered gene copies for the condition to appear.
Refractive error — Need for glasses (nearsighted, farsighted, astigmatism). Separate from Alström but managed with lenses.
Renal — Pertaining to the kidneys.
Renin-angiotensin system — A blood-pressure regulation system. Many heart and kidney medications target this.
Respite care — Temporary care for a medically complex person to give the regular caregivers a break.
Restrictive cardiomyopathy — A type of heart disease where the heart muscle is stiff and can't fill properly. Sometimes seen in adults with Alström. → Read more
Retina — The light-sensitive tissue at the back of the eye.
Retinal pigment epithelium (RPE) — A layer behind the retina that supports photoreceptors. Affected in Alström progression.
Retinitis pigmentosa (RP) — A group of inherited retinal degenerations. Different pattern than Alström — rod-cone dystrophy rather than cone-rod.
Rods — One of two types of photoreceptors. Handle dim light and peripheral vision. Affected later than cones in Alström.
S
Schema markup (JSON-LD) — Structured data added to webpages so search engines can understand the content. Important for SEO ranking.
Scoliosis — Sideways curvature of the spine. Common in Alström, sometimes requiring surgery. → Read more
Sensorineural hearing loss — Hearing loss caused by problems in the inner ear or auditory nerve. The type seen in Alström.
SGLT2 inhibitor — A class of medications (like empagliflozin, dapagliflozin) that lower blood sugar and protect heart and kidney function. Increasingly used in Alström.
SLP (speech-language pathologist) — Therapist who works on speech, language, and communication. → Read more
Sleep apnea — See Obstructive sleep apnea.
Slit-lamp examination — Examination of the front of the eye using a special microscope. Standard part of an eye exam.
SSDI (Social Security Disability Insurance) — US disability benefit based on work history. Alström qualifies under Compassionate Allowances.
SSI (Supplemental Security Income) — US disability benefit for low-income individuals.
Steatosis — Fat accumulation. Hepatic steatosis = fatty liver.
Stria vascularis — A specialized structure in the cochlea. Believed to be involved in Alström-related hearing loss.
Subspecialist — A doctor with deeper expertise within a specialty (e.g., a pediatric retinal specialist within ophthalmology).
Supernumerary teeth — Extra teeth. Sometimes reported in Alström.
Surveillance — Routine monitoring (typically annual) to catch problems early. The cornerstone of Alström care.
Synthetic insulin — Manufactured insulin used to treat diabetes when the body's own insulin isn't enough.
T
T2DM (type 2 diabetes mellitus) — The form of diabetes nearly universal in Alström. → Read more
Tactile signing — Sign language conveyed through touch, used by people who are deafblind.
Targeted gene panel — A genetic test that sequences a specific set of genes related to a condition or set of conditions.
Telehealth — Medical visits conducted by video or phone. → Read more
TODHH (Teacher of the Deaf and Hard of Hearing) — Educational specialist for deaf and hard-of-hearing students.
Triglycerides — A type of blood fat. Often elevated in Alström. → Read more
Trio sequencing — Genetic testing of a child plus both parents. Used in critical-illness situations to expedite diagnosis.
Truncal obesity — Weight concentrated around the abdomen. The pattern seen in Alström.
TVI (Teacher of Students with Visual Impairments) — US educational specialist for visually-impaired students. Provides Braille, technology, and other instruction. → Read more
Tympanometry — A hearing test that measures middle-ear function and rules out fluid or pressure problems.
U
Urodynamic study — Test that measures bladder filling and emptying patterns. Used to diagnose detrusor-urethral dyssynergia.
Urologist — Specialist in urinary system and male reproductive system.
Usher Syndrome — A different inherited deafblindness syndrome. Doesn't include cardiomyopathy or diabetes. → Read more
UTI (urinary tract infection) — Bacterial infection of the urinary system. More common in people with bladder dysfunction.
V
Variant — A genetic change. May be benign, pathogenic, or uncertain.
Variant of uncertain significance (VUS) — A genetic change where the available evidence isn't enough to classify it as either disease-causing or benign. → Read more
Vestibular system — The balance system of the inner ear.
Visual acuity — How sharp central vision is. Measured on charts (Snellen, ETDRS, Lea symbols).
Visual field — The full extent of what you can see at one time, including peripheral vision.
Vocational rehabilitation (VR) — US state-run services that support people with disabilities in employment and education.
W
WCAG — Web Content Accessibility Guidelines. The standard for making websites accessible to people with disabilities.
Whole-exome sequencing (WES) — Genetic test that sequences all exons in the genome. Used when targeted panels haven't found an answer.
Whole-genome sequencing (WGS) — Genetic test that sequences the entire genome. The most comprehensive test available.
X–Z
Xanthoma — A yellowish skin bump caused by deposits of fat. Can occur with very high triglycerides.
ZEB1 — A gene unrelated to Alström but sometimes mentioned in differential diagnosis discussions.
Frequently Asked Questions
Is this glossary medically reviewed?
Yes — by [Medical Reviewer Name and Credentials, to be added]. Updated periodically as new research and terminology emerges.
How do I learn more about a specific term?
Most terms link to a more detailed article. For terms not covered here, contact us or one of the patient organizations (ASI, ASUK).
Can I suggest a term to add?
Yes — feedback welcome via the site contact form.
This glossary is for informational purposes only and is not a substitute for medical advice from your or your child's healthcare team. Last updated April 30, 2026.