De novo truncating mutations in AHDC1 in people with syndromic expressive language delay, hypotonia, and sleep apnea

Original research report by F. Xia et al. (2014.)

Read the report here.

The authors used whole-exome sequencing to identify four children, ranging from 18 months to 11 years of age, with changes in the AHDC1 gene. It is important to note the wide age range of the children in this study. Children achieve various developmental milestones at different ages, so broad comparisons across age groups can be difficult.

Three of the four children with changes in the AHDC1 gene have a history of stopping breathing during sleep (sleep apnea). All four have some level of intellectual disability and/or developmental delay, low muscle tone (hypotonia), failure to thrive, mild differences in facial features, and some degree of speech impairment. Two children (ages 18 months and 11 years) were assessed as being nonverbal, one child (age 4) was assessed as speaking two words, and one child (age 8) was assessed as verbal, speaking his first words after age 1 and receiving ongoing speech therapy.

This group of clinical features is not currently associated with a diagnosed condition. AHDC1 changes are rare, and the researchers believe these changes may be an underlying cause of the features observed in these people. With further research and more data from families, a stronger conclusion can be made regarding how changes in AHDC1 are associated with developmental delay and sleep problems.