Ring chromosome 7 syndrome

Ring formation on chromosome 7 is very rare. A ring chromosome is formed when two ends of a chromosome fuse together, forming a ring structure; this can happen with or without terminal chromosomal deletions. Clinical manifestations of ring chromosome 7 syndrome, r(7), include growth and developmental delay, speech delay, intellectual disability, seizures, cardiovascular anomalies, dermatological abnormalities, cranial/facial anomalies, genital/skeletal system abnormalities. Bangun et al. introduce a new case of r(7). The 4-years-old boy presented with bilateral cleft lip/palate, microcephaly, clenched toes, nevi, café-au-lait spots, hearing impairment, a history of epilepsy (which stopped after he was 2-years-old), and severe intellectual disability. The patient did not have other recorded r(7) manifestations such as heart and genital abnormalities. The proband was referred to the Craniofacial Centre for cleft lip and palate surgery when he was 5 months old and had bilateral labiaplasty performed; he later had successful cheiloplasty and palatoplasty. Karyotype revealed 46, XY,r(7) (p22q36) and he was diagnosed with ring chromosome syndrome 7. Almost all previously reported patients with r(7) were mosaics. There is no evidence of mosaicism in this patient although apparently no other tissues (above blood cells) were examined. All of the r(7) cases reviewed exhibited dysmorphic features, but they varied in severity: most of the babies had low birth weight (72.7 % of patients), microcephaly (81.8%), all had growth/developmental delay, skin anomalies (86.4%), cleft lip with or without cleft palate (13.6% and 22.7% respectively), heart abnormalities (18.2%), seizures (27.3%), and intellectual disability (50%). In the case of this proband, the plastic surgeon was the first responder for the referral to genetics. Because of this, the authors’ findings support an early diagnosis/genetic testing and use of a multidisciplinary team to maximize the care of r(7) patients.

Bangun et al. “Bilateral Cleft Lip and Palate in Ring Chromosome 7 Syndrome: A Case Report and Review of Clinical Characteristics”. “The Cleft Palate Craniofacial Journal” 2023, online ahead of print.