These often resolve by around 4–5 years of age with specialist intervention, and so would not meet criteria for DLD. Where such problems continue beyond five years of age, they are usually accompanied by problems in broader language domains and have a poorer prognosis, so a diagnosis of DLD with SSD is then appropriate. Relationship with other neurodevelopmental disorders
DLD often co-occurs with milder neurodevelopmental disorders of unknown origin, such as attention-deficit hyperactivity disorder, developmental dyslexia or developmental coordination disorder. These do not preclude a diagnosis of DLD, but should be noted as co-occurring conditions. Risk factors
It is generally accepted that DLD is strongly influenced by genetic factors. The best evidence comes from the twin study method. Two twins growing up together are exposed to the same home environment, yet may differ radically in their language skills. Such different outcomes are, however, much more common in fraternal (non-identical) twins, who are genetically different. Identical twins share the same genes and tend to be much more similar in language ability. There can be some variation in the severity and persistence of DLD in identical twins, indicating that non-genetic factors affect the course of disorder, but it is unusual to find a child with DLD who has an identical twin with typical language.There was considerable excitement when a large, multigenerational family with a high rate of DLD were found to have a mutation of the FOXP2 gene just in the affected family members.
The leukemic cells contained acquired mutations in several genes that had not previously been associated with the disease. References
External links

PDQ statement on AML for health professionals at National Cancer Institute