Clinical and molecular genetic study of Cockayne syndrome accompanied with nephrotic syndrome in a family

Abstract

Objective To analyze the clinical and genetics characteristics in twin sisters with Cockayne syndrome. Methods The identical twin sisters visited the Affiliated Children′s Hospital of Capital Institute of Pediatrics in December 2016.The clinical presentations, course of treatment, blood biochemistry, metabolic screening and whole exon sanger sequencing were analyzed. Results These two patients were referred at 4 years and 5 months of age for growth failure and developmental delay.The younger sister manifested short stature (only 97 cm), low weight (14.0 kg) and little head circumference (43 cm), and the elder sister manifested short stature (only 98 cm), low weight (15.5 kg) and little head circumference (43 cm). They were born with out adverse event, and then they kept the head up at 8 months of age.They could sit at 10 months of age, but they had not acquired independent walking ability up till now.They spoke their first words at 2 year of age, and made little progress after that.They had a variety of abnormal clinical features including cognitive deficits, microcephaly, thin pointy nose, sunken eyes, small chin, photosensitive rash, hearing impairment, volitional tremor and hypermyotonia.They had been diagnosed as nephrotic syndrome at 4.5 years old, with little response to prednisone.The renal biopsy revealed minimal change nephropathy.Cerebrum and cerebellum atrophy was detected by magnetic resonance image scanning.Two heterozygous ERCC8 mutations in both patients, c.394_398delTTACA and large fragment deletion, were identified in the patient.The c. 394_398delTTACA mutation originated from his father.The exon 4 deletion from his mother caused the defection of the protein. Conclusions Cockayne syndrome is a rare autosomal recessive disease.It is not only characterized by developmental delay, microcephaly, sunken eyes, photosensitive rash and auditory abnormalities, but also can be involved in nephrotic syndrome.Cockayne syndrome can be caused by compound heterozygous mutation, including c. 394_398delTTACA and a large fragment deletion of exon 4 in ERCC8. Key words: Cockayne syndrome; Nephrotic syndrome; ERCC8 gene; Microcephaly