Development, Behavior, and Hidden Symptoms

While epilepsy often takes center stage in idic15 and Dup15q syndrome, the condition also brings a set of developmental and physical challenges that significantly impact a child’s daily life. These “hidden” symptoms can range from muscle tone issues to gastrointestinal distress, and understanding them is key to supporting your child’s overall wellbeing.

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Motor Development & Hypotonia

Almost all children with idic15 experience central hypotonia, or low muscle tone ^[1][2]. This is not a problem with the muscles themselves, but rather with how the brain sends signals to keep those muscles active and ready for use.

• Delayed Milestones: Because of this low tone, children reach motor milestones much later than their peers. For instance, independent walking may not occur until well into toddlerhood, or even later, depending on the child ^[3].
• Gait and Balance: When children do begin to walk, they often have a “wide-based” gait, poor postural control, and may tire more easily than other children ^[3][4].
• Therapy Needs: Early and consistent physical therapy is a cornerstone of care, focusing on core strength and stability ^[4].

The Challenge of Gastrointestinal (GI) Issues

GI problems are incredibly common but frequently go undiagnosed. Research shows that roughly 77% of children with idic15 and 87% with interstitial duplications struggle with GI symptoms ^[5].

• Common Culprits: Constipation (60%) and gastroesophageal reflux (57%) are the most frequent issues ^[5].
• The “Pain Mask”: Many children with idic15 have a high pain threshold ^[6]. They may not cry or show obvious signs of pain even with severe reflux or impaction. Instead, they may express discomfort through “behavioral outbursts,” such as increased irritability, aggressiveness, or self-injury ^[5].
• Tracking Patterns: Caregivers are highly encouraged to maintain a Behavior and Bowel Movement Diary. This can help providers spot cyclic patterns of pain that might otherwise be dismissed as purely psychiatric or behavioral ^[5].

Behavior and the Spectrum of Autism

Autism Spectrum Disorder (ASD) is a core feature of the syndrome, with a very high “penetrance” (meaning most children with the duplication will meet the criteria for autism) ^[7][8].

While children with idic15 often share the social and communication challenges seen in non-syndromic autism, they may also show specific strengths in social interest that can be built upon in therapy ^[4]. However, they often face more significant challenges with daily living skills and motor coordination than other children with autism of the same age ^[4].

Sleep: The Third Pillar

Sleep disturbances are reported in a vast majority of families and are closely linked to both behavior and epilepsy ^[2][9].

• Sleep Architecture: EEG studies show that children with idic15 often have abnormal brain wave patterns during sleep, including the same beta oscillations seen during the day ^[10][11].
• The Sleep-Seizure Cycle: Sleep deprivation can lower the “seizure threshold,” making it more likely for a child to have an event ^[2]. Conversely, certain types of electrical activity during sleep, such as Continuous Spike and Wave During Slow Sleep (CSWS), can interfere with a child’s ability to learn and remember ^[10].
• Impact on Behavior: Poor sleep is a major driver of daytime behavioral challenges. Addressing sleep through routines, environmental changes, or medications can often lead to improvements in a child’s mood and focus during the day ^[2][9].