The features of this syndrome vary widely, even among members of the same family, and affect many parts of the body. Characteristic signs and symptoms may include birth defects such as congenital heart disease, defects in the palate, most commonly related to neuromuscular problems with closure (velopharyngeal insufficiency), learning disabilities, mild differences in facial features, and recurrent infections. Infections are common in children due to problems with the immune system's T cell-mediated response that in some patients is due to an absent or hypoplastic thymus.<unk>  may be first spotted when an affected newborn has heart defects or convulsions from hypocalcemia due to malfunctioning parathyroid glands and low levels of parathyroid hormone (parathormone). Affected individuals may also have other kinds of birth defects including kidney abnormalities and significant feeding difficulties as babies. Gastrointestinal issues are also very common in this patient population. Digestive motility issues may result in constipation. Disorders such as hypothyroidism and hypoparathyroidism or thrombocytopenia (low platelet levels), and psychiatric illnesses are common late-occurring features. Microdeletions in chromosomal region 22q11.2 are associated with a 20 to 30-fold increased risk of schizophrenia. Studies provide various rates of 22q11.2DS in schizophrenia, ranging from 0.5 to 2.0% and averaging about 1.0%, compared with the overall estimated 0.025% risk of the 22q11.2DS in the general population. Salient features can be summarized using the mnemonic CATCH-22 to describe 22q11.2DS, with the 22 signifying the chromosomal abnormality is found on the 22nd chromosome, as below: * Cardiac abnormality (commonly interrupted aortic arch, truncus arteriosus and tetralogy of Fallot) * Abnormal facies * Thymic aplasia * Cleft palate * Hypocalcemia/hypoparathyroidism Individuals can have many possible features, ranging in number of associated features and from the mild to the very serious. Symptoms shown to be common include: This syndrome is characterized by incomplete penetrance. Therefore, there is a marked variability in clinical expression between the different patients. This often makes early diagnosis difficult. Cognitive impairments Children with<unk>  have a specific profile in neuropsychological tests. They usually have a below-borderline normal IQ, with most individuals having higher scores in the verbal than the nonverbal domains. Some are able to attend main-stream schools, while others are home-schooled or in special classes. The severity of hypocalcemia early in childhood is associated with autism-like behavioral difficulties. Adults with<unk>  are a specifically high-risk group for developing schizophrenia. About 30% have at least one episode of psychosis and about a quarter develop schizophrenia by adulthood. Individuals with<unk>  also have a higher risk of developing early onset Parkinson's disease (PD). Diagnosis of Parkinson's can be delayed by up to 10 years due to the use of antipsychotics, which can cause parkinsonian symptoms. Speech and language Current research demonstrates a unique profile of speech and language impairments is associated with 22q11.2DS. Children often perform lower on speech and language evaluations in comparison to their nonverbal IQ scores. Common problems include hypernasality, language delays, and speech sound errors. Hypernasality occurs when air escapes through the nose during the production of oral speech sounds, resulting in reduced intelligibility. This is a common characteristic in the speech and language profile because 69% of children have palatal abnormalities. If the structure of the soft palate velum is such that it does not stop the flow of air from going up to the nasal cavity, it will cause hypernasal speech. This phenomenon is referred as velopharyngeal inadequacy (VPI). Hearing loss can also contribute to increased hypernasality because children with hearing impairments can have difficulty self monitoring their oral speech output. The treatment options available for VPI include prosthesis and surgery. Difficulties acquiring vocabulary and formulating spoken language (expressive language deficits) at the onset of language development are also part of the speech and language profile associated with the 22q11.2 deletion. Vocabulary acquisition is often severely delayed for preschool-age children. In some recent studies, children had a severely limited vocabulary or were still not verbal at 2–3 years of age. School-age children do make progress with expressive language as they mature, but many continue to have delays and demonstrate difficulty when presented with language tasks such as verbally recalling narratives and producing longer and more complex sentences. Receptive language, which is the ability to comprehend, retain, or process spoken language, can also be impaired, although not usually with the same severity as expressive language impairments. Articulation errors are commonly present in children with<unk> . These errors include a limited phonemic (speech sound) inventory and the use of compensatory articulation strategies resulting in reduced intelligibility. The phonemic inventory typically produced consists of sounds made in the front or back of the oral cavity such as: /p/, /w/, /m/, /n/, and glottal stops. Sound made in the middle of the mouth are completely absent. Compensatory articulation errors made by this population of children include: glottal stops, nasal substitutions, pharyngeal fricatives, linguapalatal sibilants, reduced pressure on consonant sounds, or a combination of these symptoms. Of these errors, glottal stops have the highest frequency of occurrence. It is reasoned that a limited phonemic inventory and the use of compensatory articulation strategies is present due to the structural abnormalities of the palate. The speech impairments exhibited by this population are more severe during the younger ages and show a trend of gradual improvement as the child matures.
DiGeorge syndrome
Smith–Lemli–Opitz syndrome
Langer–Giedion syndrome
Alagille syndrome
ATR-16 syndrome
Goldenhar syndrome
ATR-X syndrome
VACTERL association