Identification of two novel homozygous mutations in ERCC8 gene in two unrelated consanguineous families with Cockayne syndrome from Iran.

BACKGROUND: Cockayne syndrome (CS) is a rare autosomal recessive disorder with characteristic multisystem involvement including pre- or post-natal growth failure, progressive neurological dysfunction, psychomotor retardation, cerebral atrophy, microcephaly and mental retardation, due to mutations in either the ERCC8/CSA or ERCC6/CSB gene. METHOD: We present two Iranian patients with remarkable growth failure, developmental delay, microcephaly, severe speech delay, vision problem, sun sensitivity, hearing loss, dental anomalies, unstable gait, mild contractures in knees, kyphosis and spasticity in lower limbs, balance disorders and typical dysmorphic features including long nose, aged face, large ears and sunken eyes. Clinical evaluation, magnetic resonance imaging, Peripheral blood karyotype, Multiplex ligation-dependent probe amplification (MLPA), and whole-exome sequencing were used to characterize etiology in two patients from two unrelated consanguineous families of Iranian descent with Cockayne syndrome. RESULTS: We detected two novel pathogenic mutations in two unrelated families, a homozygous duplication mutation (c.317_320dupAGTG, p.Trp107Ter) and a splicing variant (c.481 + 1G > A) in ERCC8 gene. CONCLUSION: WES results together with the characteristic clinical manifestations of Cockayne syndrome, provided an accurate diagnosis for two patients. Also, our study identified two novel variants in Iranian families.

Clinical and molecular genetic study of Cockayne syndrome accompanied with nephrotic syndrome in a family / 中华实用儿科临床杂志

Objective To analyze the clinical and genetics characteristics in twin sisters with Cockayne syn-drome.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.

Clinical characteristics, treatment and follow-up of Cockayne syndrome with renal involvement / 临床儿科杂志

Objective To explore the clinical features, treatment and follow-up of Cockayne syndrome with renal involvement. Method The clinical data of one child with Cockayne syndrome confirmed by gene detection with renal injury were reviewed, and the clinical features of renal involvement in Cockayne syndrome were summarized. Results A male child aged 3 years and 8 months had clinical manifestations of mental retardation, growth retardation, special face and photosensitive dermatitis, and renal involvement was manifested by nephrotic syndrome. Cranial CT showed symmetrically calcification in bilateral basal ganglia. The targeted next generation sequencing results showed homozygous mutations of c.394_398del and p.Leu132Asnfs in ERCC8 gene (NM_000082) of the child, and the same heterozygous mutation was found in both his parents (non-consanguineous marriage). After the diagnosis of nephrotic syndrome, full dose prednisone was given for experimental treatment. The urine protein decreased but did not disappear, which was considered hormone resistance. After 4 months of combined treatment with cyclosporin, the urine protein turned negative. During 20 months of follow-up, urine protein remained negative and renal function remained stable. The renal involvement in Cockayne syndrome was seldomly reported, and its clinical manifestations are heterogeneous. Condusion Renal involvement in Cockayne syndrome may be manifested with nephrotic syndrome which should be noticed.

A case of Cockayne syndrome caused by ERCC8 gene mutation / 临床儿科杂志

Objective To explore the clinical,radiological and gene mutation features ofERCC8 gene in one patient with Cockayne syndrome.Methods Clinical and radiological data of a girl diagnosed with Cockayne syndrome through gene detection were retrospectively analyzed.Next-generation sequencing was used to detect genetic cause.Sanger sequencing was used to confirm the candidate variants and detect mutations in her parents and sister.ResuRs The patient showed psychomotor retardation,growth failure,special face,and light sensitivity.Neurological examination revealed noticeable developmental delay,motor impairment,spastic paralysis,and cerebellar ataxia.Brain MRI revealed symmetrical demyelination of bilateral centrum semiovale and periventricular white matter.The cerebellum was atrophic.The patient was found to have compound heterozygous mutations of c.397C＞T(p.Q133X) and c.394_398del(p.L132fs).Sanger sequencing showed these two mutations were inherited from her mother and father respectively.Conclusions Next-generation sequencing technology is a useful tool for the detection of mutation in ERCC8 gene,which is valuable for the diagnosis of Cockayne syndrome.These two mutations expanded the mutation spectrum of Cockayne syndrome in Chinese population.