Auditory neuropathy–optic atrophy syndrome (ANOA) is a rare neurological condition in which the hearing nerve pathway does not transmit sound signals properly ...

Auditory dys-synchrony (auditory neuropathy spectrum disorder, ANSD) is a hearing disorder in which sound enters the ear normally and the outer hair cells of ...

Auditory neuropathy is a hearing disorder where the inner ear (the cochlea) often “hears” sound normally, but the message does not travel correctly along the ...

Okamoto syndrome is a very rare genetic condition that affects how a child grows and develops. It is usually caused by a change (variant) in a single gene ...

Neurodevelopmental disorder–craniofacial dysmorphism–cardiac defect–hip dysplasia syndrome is a very rare, genetic, multi-system condition. Most babies show ...

Spondylolysis means there is a small break (a “stress fracture”) or a thinning/defect in a narrow bridge of bone at the back of a vertebra called the pars ...

Au–Kline syndrome (AKS) is a very rare, genetic condition that affects many body systems. Most people with AKS have weak muscle tone in infancy (hypotonia), ...

Atypical Progeroid Syndrome (APS) is a very rare genetic condition in which a person shows signs that resemble early aging (progeroid features) but does not ...

Atypical Werner syndrome (AWS) is a group of rare “progeroid” conditions that look like classic Werner syndrome—early graying, thin tight skin, short stature, ...

Atypical Rett syndrome (sometimes called a “variant” of Rett) is a neurodevelopmental condition in which a child—most often a girl—shows several hallmark Rett ...

Atypical progressive supranuclear palsy (PSP) is a brain disease where certain cells slowly get damaged by an abnormal protein called 4-repeat tau. This damage ...

Atypical Norrie disease due to monosomy Xp11.3 is a rare condition that happens when a small piece of the short arm of the X chromosome (region Xp11.3) is ...

Atypical juvenile parkinsonism means parkinsonism that starts in children, teens, or very young adults and does not look like the “typical” adult Parkinson’s ...

Atypical hypotonia-cystinuria syndrome is a very rare, inherited condition that combines weak muscle tone from birth (hypotonia) with a kidney transport ...

Hemolytic-uremic syndrome without diarrhea—most often called atypical HUS (aHUS)—is a rare, serious blood-and-kidney disorder. Tiny clots form in the body’s ...

Atypical hemolytic-uremic syndrome is a rare disease where the body’s complement system (part of the immune system) becomes overactive and attacks tiny blood ...

Hereditary ATTRV30M amyloidosis is a genetic disease in which a change (mutation) in the transthyretin (TTR) gene—most often the Val30Met variant—causes the ...

ATTRV30M amyloidosis is a genetic disease. It happens when a change (variant) in the transthyretin (TTR) gene—specifically the Val30Met (V30M) variant—makes ...

ATTRV122I amyloidosis is a genetic disease where a small change in the transthyretin (TTR) gene (valine → isoleucine at position 122; sometimes numbered 142) ...

Hereditary flat adenoma syndrome (HFAS)” is an older name for a milder form of familial adenomatous polyposis (FAP). Today, most experts call it attenuated ...