What are the signs and symptoms of Adenylosuccinase deficiency? The signs and symptoms of adenylosuccinase deficiency vary greatly from person to person. Seizures are observed in 60 percent of affected individuals. Seizures may begin within the first month of life and, in many cases, are the first sign of the condition. Some of the neurological symptoms include floppiness (hypotonia) with severe tension of the hands and feet (hypertonia); muscle wasting; muscle twitchings of the tongue or hands and feet; and crossed eyes (strabismus). Almost all affected individuals experience delayed motor milestones ranging from mild to severe. In the first years of life, growth delay has been observed in 30 percent of affected individuals, mainly related to feeding problems. Autism has been found to be present in one-third of cases. Some children display unusual behavior such as stereotyped behavior, (hand washing movements, repetitive manipulation of toys, grimacing, clapping hands, rubbing feet, and inappropriate laughter), aggressive behavior, temper tantrums, impulsivity, hyperactivity, short attention span, and hypersensitivity to noise and lights. Many patients show severe intellectual disability, and language delay. The Human Phenotype Ontology provides the following list of signs and symptoms for Adenylosuccinase deficiency. 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) Happy demeanor 5% Microcephaly 5% Aggressive behavior - Anteverted nares - Autism - Autosomal recessive inheritance - Brachycephaly - Brisk reflexes - Cerebellar atrophy - Cerebral atrophy - Cerebral hypomyelination - CNS hypomyelination - Delayed speech and language development - Gait ataxia - Growth delay - Hyperactivity - Inability to walk - Inappropriate laughter - Infantile onset - Intellectual disability - Long philtrum - Low-set ears - Muscular hypotonia - Myoclonus - Nystagmus - Opisthotonus - Poor eye contact - Prominent metopic ridge - Seizures - Self-mutilation - Severe global developmental delay - Short nose - Skeletal muscle atrophy - Smooth philtrum - Strabismus - Wide mouth - 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.