Question: What is (are) 16q24.3 microdeletion syndrome ?
Answer: 16q24.3 microdeletion syndrome is a chromosome abnormality that can affect many parts of the body. People with this condition are missing a small piece (deletion) of chromosome 16 at a location designated q24.3. Signs and symptoms may include developmental delay, characteristic facial features, seizures and autism spectrum disorder. Chromosome testing of both parents can provide more information on whether or not the microdeletion was inherited. In most cases, parents do not have any chromosomal anomaly. However, sometimes one parent has a balanced translocation where a piece of a chromosome has broken off and attached to another one with no gain or loss of genetic material. The balanced translocation normally does not cause any signs or symptoms, but it increases the risk for having an affected child with a chromosomal anomaly like a microdeletion. Treatment is based on the signs and symptoms present in each person. To learn more about chromosomal anomalies in general, please visit our GARD webpage on Chromosome Disorders.
Source: GARD

Question: What are the symptoms of 16q24.3 microdeletion syndrome ?
Answer: What are the signs and symptoms of 16q24.3 microdeletion syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for 16q24.3 microdeletion 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 pinna 90% Autism 90% High forehead 90% Abnormality of neuronal migration 50% Abnormality of the palate 50% Aplasia/Hypoplasia of the corpus callosum 50% Cognitive impairment 50% Frontal bossing 50% Optic atrophy 50% Pointed chin 50% Seizures 50% Thrombocytopenia 50% Ventriculomegaly 50% Wide mouth 50% Abnormality of the hip bone 7.5% Abnormality of the mitral valve 7.5% Anteverted nares 7.5% Astigmatism 7.5% Cryptorchidism 7.5% Feeding difficulties in infancy 7.5% Hearing impairment 7.5% Highly arched eyebrow 7.5% Hypertrophic cardiomyopathy 7.5% Kyphosis 7.5% Long face 7.5% Long philtrum 7.5% Macrocytic anemia 7.5% Myopia 7.5% Narrow forehead 7.5% Neurological speech impairment 7.5% Nystagmus 7.5% Otitis media 7.5% Preauricular skin tag 7.5% Proximal placement of thumb 7.5% Scoliosis 7.5% Strabismus 7.5% Thick lower lip vermilion 7.5% Triangular face 7.5% Upslanted palpebral fissure 7.5% Ventricular septal defect 7.5% Visual impairment 7.5% 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