MedGen

A chromosomal disorder consisting of the absence of a part of a chromosome. [from MONDO]

The newly described syndrome includes severe intellectual deficit with pronounced speech delay, behavioural abnormalities including hyperactivity and inappropriate laughter, short stature and seizures. To date, fifteen patients have been reported. Dysmorphic features include microcephaly, wide and open mouth, a tented upper lip, and prominent incisors. The majority of cases present with stereotypic repetitive behaviour, disturbed sleep pattern and a broad-based gait. Skeletal abnormalities include generalised brachydactyly with small hands and feet. The size of the deletions is variable the critical region includes a single gene, MBD5. [from SNOMEDCT_US]

MBD5 haploinsufficiency is a neurodevelopmental disorder characterized by developmental delay, intellectual disability, severe speech impairment, seizures, sleep disturbances, and abnormal behaviors. Most children lack speech entirely or have single words, short phrases, or short sentences. Seizures are present in more than 80% of children; onset is usually around age two years. Sleep disturbances, present in about 90%, can result in excessive daytime drowsiness. Abnormal behaviors can include autistic-like behaviors (80%) and self-injury and aggression (>60%). [from GeneReviews]