Question: What is (are) 22q13.3 deletion syndrome ?
Answer: 22q13.3 deletion syndrome, also known as Phelan-McDermid syndrome, is a chromosome abnormality caused by the loss (deletion) of a small piece of chromosome 22. The deletion occurs near the end of the long arm (or q arm) at a location designated as q13.3. The signs and symptoms of this condition vary widely from person to person. Common symptoms include low muscle tone (hypotonia), intellectual disability, delayed or absent speech, abnormal growth, tendency to overheat, large hands, and abnormal toenails. Affected individuals may have characteristic behaviors, such as mouthing or chewing on non-food items, decreased perception of pain, and autistic-like behaviors. The loss of a particular gene on chromosome 22, called the SHANK3 gene, is likely responsible for many of the signs and symptoms of 22q13.3 deletion syndrome. Additional genes within the deleted region probably contribute to the variable features of the syndrome.
Source: GARD

Question: What are the symptoms of 22q13.3 deletion syndrome ?
Answer: What are the signs and symptoms of 22q13.3 deletion syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for 22q13.3 deletion syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of the eyelashes 90% Accelerated skeletal maturation 90% Delayed speech and language development 90% Hypoplastic toenails 90% Impaired pain sensation 90% Large hands 90% Muscular hypotonia 90% Neonatal hypotonia 90% Neurological speech impairment 90% Tall stature 90% Autism 75% Bruxism 75% Hyperorality 75% Long eyelashes 75% Poor eye contact 75% Abnormal nasal morphology 50% Abnormality of immune system physiology 50% Behavioral abnormality 50% Broad-based gait 50% Bulbous nose 50% Deeply set eye 50% Dolichocephaly 50% Full cheeks 50% Heat intolerance 50% Hypohidrosis 50% Macrotia 50% Malar flattening 50% Palpebral edema 50% Pointed chin 50% Ptosis 50% Sacral dimple 50% Thick eyebrow 50% Unsteady gait 50% Wide nasal bridge 50% 2-3 toe syndactyly 33% Clinodactyly of the 5th finger 33% Dental malocclusion 33% Epicanthus 33% Episodic vomiting 33% Gastroesophageal reflux 33% High palate 33% Long philtrum 33% Lymphedema 33% Seizures 33% Strabismus 33% Aggressive behavior 25% Hearing impairment 20% Arachnoid cyst 15% Tongue thrusting 15% Cellulitis 10% Abnormality of the periventricular white matter 7.5% Abnormality of the teeth 7.5% Aplasia/Hypoplasia of the corpus callosum 7.5% Cerebral cortical atrophy 7.5% Cognitive impairment 7.5% Delayed CNS myelination 7.5% Macrocephaly 7.5% Obesity 7.5% Patent ductus arteriosus 7.5% Polycystic kidney dysplasia 7.5% Umbilical hernia 7.5% Ventricular septal defect 7.5% Ventriculomegaly 7.5% Vesicoureteral reflux 7.5% Cortical visual impairment 6% Microcephaly 1% Concave nasal ridge - Feeding difficulties - Generalized hypotonia - Hyporeflexia - Intellectual disability, moderate - Motor delay - Prominent supraorbital ridges - Protruding ear - Short chin - Sporadic - Toenail dysplasia - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD