[Clinical and molecular genetic analysis of Angelman syndrome with oculocutaneous albinism type 2: A case report and literature review].

To summarize the clinical diagnosis and treatment process and genetic test results and characteristics of one child with Angelman syndrome (AS) complicated with oculocutaneous albinism type 2 (OCA2), and to review the literature. "Angelman syndrome" "P gene" and "Oculocutaneous albinism type 2" were used as keywords to search at CNKI, Wanfang, and PubMed databases (from creation to December 2019). Then all the patients were analyzed. The patient in this study was a girl aged 1 year. After birth, she was found to present as white body, yellow hair, and nystagmus. She could raise her head at the age of 2 months and turn over at the age of 7 months. The head circumference was 42 cm and she could not sit alone or speak at present. Trio-based exome sequencing revealed that the patient carried a homozygous mutation of c.168del (p.Gln58ArgfsTer44) in the P gene, and her father was heterozygous and her mother was wild-type. The detection of copy number variation showed deletion on the maternal chromosome at 15q11.2-13.1 region (P gene located in this region) in the patient. Until December 2019, a total of 4 cases in the 4 literature had been reported. Adding our case here, the 5 cases were summarized and found that all the cases showed white skin, golden hair, and shallow iris after birth. Comprehensive developmental delay was found around 6 months of age after birth, and the language remained undeveloped in 2 cases till follow-up into childhood. Seizures occurred in 4 patients. Two cases had ataxia. All the 5 cases had acquired microcephaly. Two cases had a family history of albinism. Electroencephalogram monitoring was completed in 3 cases and the results were abnormal. Genetic tests showed that all the 5 cases had deletion on maternal chromosome at 15q11-13 region. Four cases carried mutation of P gene on paternal chromosome. And 1 case was clinically diagnosed as OCA2 without P gene test. AS combined with OCA2 is relatively rare. OCA2 is easily diagnosed based on the obvious clinical manifestations after birth. When combined with clinical manifestations such as neurodevelopmental delay, it might indicate the possibility of AS that is hardly diagnosed clinically at an early stage. Genetic tests can reveal the cross-genetic phenomenon of AS and OCA2 and the complex of them can be eventually diagnosed.

[Genotype and phenotype of children with KCNA2 gene related developmental and epileptic encephalopathy].

Objective: To investigate the genotype and phenotype of children with KCNA2 gene related developmental and epileptic encephalopathy (DEE). Methods: Clinical data including the manifestations and electroencephalogram of 8 children with KCNA2 variants treated in the Department of Pediatrics, Peking University First Hospital from March 2017 to June 2019 were collected and analyzed retrospectively. Results: Among the 8 epileptic patients with KCNA2 variants, 5 were males and 3 were females. The age of onset was from 1 day to 11 months. The age at last follow-up ranged from 4 months to 86 months. Two variants including c.1214C>T (loss-of-function) and c.1120A>G (gain-and loss-of-function) were identified. The variant of c.1214C>T was found in six patients (case 1-6). For these patients, the age of onset was from 5 to 11 months and they were characterized by multiple seizure types. All had focal seizures and had normal development before seizure onset with developmental regression after seizure onset. The first electroencephalogram showed epileptic discharges in Rolandic region in two, epileptic discharges in Rolandic region combined with generalized discharge in one, generalized discharge with posterior predominance in two (combined with or transferred to Rolandic region during the course) and epileptic discharges in posterior region combined with generalized discharge in one. And in 5 of them the Rolandic discharges developed into epileptic electrical status (ESES) during sleep. All the six patients were still treated with a combination of multiple antiepileptic drugs. Two of them had seizure controlled at 80 months and 68 months, respectively. The variant of c.1120A>G were identified in two of eight patients (case 7 and 8) and they had seizure onset on the 1st day after birth. Their epileptic seizures were frequent and difficult to control. They had remarkably developmental delay and microcephaly since birth. One case (case 8) had a wide forehead. They had frequent seizures up to the last follow-up. In case 7, the early electroencephalogram showed epileptic discharges in temporal region, and interictal electroencephalogram at 3 months of age showed multifocal discharge with posterior and temporal region predominance. In case 8, the early electroencephalogram was normal and electroencephalogram showed burst suppression at 2 months of age, and it developed epileptiform discharge in posterior region at 1 year of age. Conclusions: KCNA2 gene variants can lead to DEE with multiple seizures types. Among them, loss-of-function c.1214C>T is the most common, and these patients have seizure onset at infancy with Rolandic discharges tended to develop into to ESES pattern. The variant of c.1120A>G is a gain-of- and loss-of-function variant, patients with c.1120A>G have seizure onset in neonatal period, the phenotype overlaps with the former but is more severe.