22q13.3 deletion syndrome

Also known as: 22q13 deletion syndrome, deletion 22q13 syndrome, deletion 22q13.3 syndrome, monosomy 22q13, Phelan-McDermid syndrome


Genetics Home Reference

22q13.3 deletion syndrome, which is also commonly known as Phelan-McDermid syndrome, is a disorder caused by the loss of a small piece of chromosome 22. The deletion occurs near the end of the chromosome at a location designated q13.3.

The features of 22q13.3 deletion syndrome vary widely and involve many parts of the body. Characteristic signs and symptoms include developmental delay, moderate to profound intellectual disability, decreased muscle tone (hypotonia), and absent or delayed speech. Some people with this condition have autism or autistic-like behavior that affects communication and social interaction, such as poor eye contact, sensitivity to touch, and aggressive behaviors. They may also chew on non-food items such as clothing. Less frequently, people with this condition have seizures.

Individuals with 22q13.3 deletion syndrome tend to have a decreased sensitivity to pain. Many also have a reduced ability to sweat, which can lead to a greater risk of overheating and dehydration. Some people with this condition have episodes of frequent vomiting and nausea (cyclic vomiting) and backflow of stomach acids into the esophagus (gastroesophageal reflux).

People with 22q13.3 deletion syndrome typically have distinctive facial features, including a long, narrow head; prominent ears; a pointed chin; droopy eyelids (ptosis); and deep-set eyes. Other physical features seen with this condition include large and fleshy hands and/or feet, a fusion of the second and third toes (syndactyly), and small or abnormal toenails. Some affected individuals have rapid (accelerated) growth.

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Monosomy 22q13 syndrome (deletion 22q13.3 syndrome or Phelan-McDermid syndrome) is a chromosome microdeletion syndrome characterized by neonatal hypotonia, global developmental delay, normal to accelerated growth, absent to severely delayed speech, and minor dysmorphic features.

Go To Source: Orphanet


Medical Term Other Names Description
Neonatal hypotonia Hypotonia, in neonatal onset, Low muscle tone, in neonatal onset [more] Muscular hypotonia (abnormally low muscle tone) manifesting in the neonatal period.
Deeply set eye Deep-set eyes, Sunken eye, Ocular depression, Enophthalmos [more] An eye that is more deeply recessed into the plane of the face than is typical.
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".
Ptosis Drooping upper eyelid, Eye drop, Blepharoptosis, Eyelid ptosis [more] The upper eyelid margin is positioned 3 mm or more lower than usual and covers the superior portion of the iris (objective); or, the upper lid margin obscures at least part of the pupil (subjective).
Pain An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.
Pointed chin Pointed mention region, Pointy chin, Witch's chin [more] A marked tapering of the lower face to the chin.
Hyperhidrosis Profuse sweating, Excessive sweating, Sweating, Increased sweating, Sweating profusely, Diaphoresis [more] Abnormal excessive perspiration (sweating) despite the lack of appropriate stimuli like hot and humid weather.
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).
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.
Metatarsus adductus Metatarsus adductovarsus, Metatarsus varus, Forefoot varus, Intoe [more] The metatarsals are deviated medially (tibially), that is, the bones in the front half of the foot bend or turn in toward the body.
Generalized hypotonia Generalized muscular hypotonia, Decreased muscle tone, Low muscle tone, Hypotonia [more] Generalized muscular hypotonia (abnormally low muscle tone).
Vomiting Emesis, Throwing up Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions.
Protruding ear Prominent ears Angle formed by the plane of the ear and the mastoid bone greater than the 97th centile for age (objective); or, outer edge of the helix more than 2 cm from the mastoid at the point of maximum distance (objective).
Nausea A sensation of unease in the stomach together with an urge to vomit.
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".
Episodic vomiting Frequent vomiting Paroxysmal, recurrent episodes of vomiting.
Dolichocephaly Narrow cranium shape, Narrow head shape, Narrow skull shape, Large dolichocephalic skull, Turridolichocephaly, Long, narrow head [more] An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture.
Global developmental delay Psychomotor developmental delay, Psychomotor retardation, Developmental delay, Lack of psychomotor development, Cognitive delay, Delayed intellectual development, Delayed milestones, Psychomotor development deficiency, Developmental retardation, Motor and developmental delay, Developmental delay in early childhood, Retarded psychomotor development, Retarded mental development, Delayed cognitive development, Retarded development, Delayed developmental milestones, Delayed development, Psychomotor development failure, Mental and motor retardation, Psychomotor delay, Delayed psychomotor development [more] A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Aggressive behavior Aggressiveness, Aggressive behaviour, physical aggression, Aggression [more] Aggressive behavior can denote verbal aggression, physical aggression against objects, physical aggression against people, and may also include aggression towards oneself.
Delayed speech and language development Poor speech acquisition, Deficiency of speech development, Impaired speech development, Speech and language difficulties, Language delayed, Language development deficit, Impaired speech and language development, Delayed speech development, Speech delay, Language delay, Speech difficulties, Delayed speech, Delayed speech acquisition, Late-onset speech development, Speech and language delay, Delayed language development [more] A degree of language development that is significantly below the norm for a child of a specified age.
Poor eye contact Difficulty in looking at another person in the eye.

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