Duplication Syndrome

What is 7q11.23 duplication syndrome?

7q11.23 duplication syndrome is a developmental disorder resulting from an extra copy of ~25 genes on the long arm of chromosome 7. Individuals who have 7q11.23 duplication syndrome have 3 copies of the genes in this region. In contrast, people in the general population have two copies of these genes. 7q11.23 duplication syndrome is sometimes referred to as “duplication of the Williams syndrome region” or “Williams syndrome duplication.” Williams syndrome is caused by a deletion of 7q11.23; thus people who have Williams syndrome have only one copy of the genes in this region. 7q11.23 duplication syndrome and Williams syndrome are associated with very different patterns of cognitive, linguistic, and behavioral strengths and weaknesses.

Although the existence of 7q11.23 duplication syndrome has been hypothesized for decades, the first person who had this syndrome was not identified until late 2004. Research on 7q11.23 duplication syndrome began immediately, and as a result of this research, several features that appear to be characteristic of the syndrome have been identified. The intellectual level of individuals with 7q11.23 ranges from moderate intellectual disability to above average intelligence. Almost all children who have this syndrome have significant expressive speech and language delay. Speech difficulties range from mild problems that are consistent with a speech delay rather than a speech disorder to severe difficulties rendering the child’s speech extremely difficult or impossible to understand. Some of the children have childhood apraxia of speech and/or oral apraxia. Signs of these disorders include difficulty planning movements of the mouth, resulting in oral groping and/or effortful, choppy speech, with accompanying difficulties in expressive language and sometimes literacy. Many of the children who do not have apraxia still show some features of that disorder. Receptive language is often stronger than expressive language. Many children speak in very short utterances and often leave out grammatical markers (e.g., past tense “–ed,” copula “is”).

7q11.23 duplication syndrome is associated with distinctive behavioral characteristics. The majority of children with this syndrome have separation anxiety disorder and/or social phobia, and many also have specific phobia (e.g., of particular types of animals). Attention deficit hyperactivity disorder (ADHD) is common, and many children also have significant behavior problems such as oppositional defiant disorder (ODD). The separation anxiety and social phobia may be secondary to the speech and expressive language problems that almost all children with 7q11.23 duplication syndrome have, and the ODD may be secondary to the separation anxiety and/or social phobia. Despite these behavioral difficulties, children with 7q11.23 duplication syndrome are often very sweet, demonstrate good imaginative and creative play skills, and have an excellent sense of humor.

Recent publication

We have recently published an article providing an overview of our research with children with 7q11.23 duplication syndrome. This article includes suggestions for speech and language intervention. Click here to view this publication.

Our research focus/interests

Our research is focused on the language, cognitive, social, and personality characteristics of infants, children, adolescents, and adults with 7q11.23 duplication syndrome and how these characteristics relate to the genetics of this syndrome.

We have several collaborators both at other universities and at the University of Louisville:

  • Dr. Colleen Morris (University of Nevada School of Medicine): Genotype/phenotype relations in 7q11.23 duplication syndrome. This project includes medical aspects of 7q11.23 syndrome as well as cognitive and behavioral aspects. We are grateful to the many clinical geneticists and neurologists at other universities who have referred patients with 7q11.23 duplication syndrome to our research.
  • Dr. Lucy Osborne (University of Toronto): Molecular genetics of 7q11.23 duplication syndrome.
  • Dr. Shelley Velleman (University of Vermont): Speech characteristics of individuals with 7q11.23 syndrome, including appropriate types of intervention.
  • Dr. Janet Woodruff-Borden (University of Louisville): Anxiety and behavioral problems.
  • Dr. Cara Cashon (University of Louisville): Early face processing and language/conceptual development.
  • Dr. Karen Berman (National Institute of Mental Health): We will soon begin neuroimaging studies of children and adults with 7q11.23 duplication syndrome. This project will focus on identifying the brain bases for some of the most distinctive characteristics of individuals with this syndrome.

Participation

If you are interested in participating in our research, please email Dr. Mervis at cbmervis@louisville.edu (please put "7q11.23 duplication syndrome" on the subject line) or call Dr. Mervis at (502) 852-3604.

Our current study is focused on individuals of all ages (from infancy through adulthood). Funds to partially offset the travel expenses of families who participate in this study are available.