Smith-Lemli-Opitz syndrome

Also known as: 7-Dehydrocholesterol reductase deficiency, RSH Syndrome, SLO syndrome, SLOS

Definition

Genetics Home Reference

Smith-Lemli-Opitz syndrome is a developmental disorder that affects many parts of the body. This condition is characterized by distinctive facial features, small head size (microcephaly), intellectual disability or learning problems, and behavioral problems. Many affected children have the characteristic features of autism, a developmental condition that affects communication and social interaction. Malformations of the heart, lungs, kidneys, gastrointestinal tract, and genitalia are also common. Infants with Smith-Lemli-Opitz syndrome have weak muscle tone (hypotonia), experience feeding difficulties, and tend to grow more slowly than other infants. Most affected individuals have fused second and third toes (syndactyly), and some have extra fingers or toes (polydactyly).

The signs and symptoms of Smith-Lemli-Opitz syndrome vary widely. Mildly affected individuals may have only minor physical abnormalities with learning and behavioral problems. Severe cases can be life-threatening and involve profound intellectual disability and major physical abnormalities.

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Orphanet

Smith-Lemli-Opitz syndrome (SLOS) is characterized by multiple congenital anomalies, intellectual deficit, and behavioral problems.

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Symptoms

Medical Term Other Names Description
Autism Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV).
Feeding difficulties Feeding problems, Poor feeding Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.
Microcephaly small cranium, Decreased circumference of cranium, Small head, Small skull, Small head circumference, Reduced head circumference, Decreased size of cranium, Decreased size of skull, Abnormally small skull, Decreased size of head, Abnormally small cranium, small calvarium, Abnormally small head [more] Occipito-frontal (head) circumference (OFC) less than -3 standard deviations compared to appropriate, age matched, normal standards (Ross JJ, Frias JL 1977, PMID:9683597). Alternatively, decreased size of the cranium.
Generalized hypotonia Generalized muscular hypotonia, Decreased muscle tone, Low muscle tone, Hypotonia [more] Generalized muscular hypotonia (abnormally low muscle tone).
Toe syndactyly Fused toes, Syndactyly of feet, Webbed toes [more] Webbing or fusion of the toes, involving soft parts only or including bone structure. Bony fusions are revered to as "bony" Syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the toes in a proximo-distal axis are refered to as "Symphalangism".
Hand polydactyly Supernumerary finger, Finger polydactyly, Extra finger, Polydactyly of the hand [more] A kind of polydactyly characterized by the presence of a supernumerary finger or fingers.
Behavioral abnormality Psychiatric disturbances, Behavioral problems, Behavioral/psychiatric abnormalities, Behavioural/Psychiatric abnormality [more] An abnormality of mental functioning including various affective, behavioural, cognitive and perceptual abnormalities.
Syndactyly Webbed fingers or toes Webbing or fusion of the fingers or toes, involving soft parts only or including bone structure. Bony fusions are revered to as "bony" syndactyly if the fusion occurs in a radio-ulnar axis. Fusions of bones of the fingers or toes in a proximo-distal axis are refered to as "symphalangism".
Intellectual disability Nonprogressive intellectual disability, Poor school performance, Mental-retardation, Dull intelligence, Nonprogressive mental retardation, Mental deficiency, Mental retardation, nonspecific, Low intelligence [more] Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

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