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.
Female ; Humans ; Albinism, Oculocutaneous/genetics* ; DNA Copy Number Variations ; Membrane Transport Proteins/genetics* ; Molecular Biology ; Mutation ; Infant

OBJECTIVE: To identify the causative variants in 13 Chinese pedigrees affected with oculocutaneous albinism (OCA) so as to provide genetic counseling and prenatal diagnosis to them. METHODS: Thirteen unrelated pedigrees with clinically diagnosed OCA were collected and classified based on the manifestation of skin and eyes. With informed consent obtained from the participants, peripheral blood samples were collected from the probands and their family members for the extraction of genomic DNA. Candidate variants were screened by targeted capture and next generation sequencing, and the results were validated by Sanger sequencing. Prenatal diagnosis was provided to the families upon their subsequent pregnancies. RESULTS: Causative variants were detected in all probands, including 10 with compound heterozygotes or homozygotes for TYR gene variants and 3 with compound heterozygotes for OCA2 gene variants. Among these, two variants [TYR: c.650G>C (p.Arg217Pro) and OCA2: c.516-2A>T] were unreported previously. The pathogenicity of the novel TYR: c.650G>C (p.Arg217Pro) variant was verified through bioinformatic analysis and prediction of three dimensional structure of the protein. Prenatal diagnosis was provided to 6 fetuses with a high risk for OCA. Four fetuses were found to be carriers, one did not carry the variants of the proband, and one was affected with OCA. CONCLUSION Identification of the pathogenic variants in the 13 probands, including 2 novel ones, has expanded the mutational spectrum of OCA and enabled genetic counseling and prenatal diagnosis for the families.
Albinism, Oculocutaneous/genetics* ; China ; Female ; Genetic Testing ; Humans ; Membrane Transport Proteins/genetics* ; Monophenol Monooxygenase/genetics* ; Mutation ; Pedigree ; Pregnancy ; Prenatal Diagnosis

OBJECTIVE: To assess the value of non-invasive prenatal testing based on cfDNA barcode-enabled single-molecule test (cfBEST) for the prenatal diagnosis of oculocutaneous albinism type I in a family. METHODS: Prenatal genetic diagnosis was carried out by using the cfBEST-based method as well as invasive prenatal diagnosis through amniocentesis. The outcome of the pregnancy was followed up. RESULTS: Non-invasive prenatal testing based on cfBEST showed a fetal DNA concentration of 6.6%, with the proportion of c.929_930insC (p.Arg311Lysfs*7) and c.1037-7T>A mutations being 45.7% and 0%, respectively. The posterior frequency of the negative results was 1, suggesting that the fetus carried neither of the two mutations. The result was consistent with that of invasive prenatal diagnosis, and the follow-up found that the fetus was normal. CONCLUSION Non-invasive prenatal testing based on cfBEST can be used to detect maternal and fetal genotypes in maternal cell-free DNA, which is clinically feasible.
Albinism ; Albinism, Oculocutaneous/genetics* ; Amniocentesis ; Cell-Free Nucleic Acids ; Female ; Humans ; Pregnancy ; Prenatal Diagnosis

OBJECTIVE: To analyze gene variants in a Chinese pedigree with oculocutaneous albinism (OCA). METHODS: Gene sequencing of the proband and his parents was performed using chip capture high-throughput sequencing and Sanger sequencing techniques, and PolyPhen-2, SIFT, MutationTaster, and FATHMM software were used to predict the function of new variants. At the same time,the pedigree and variant genes of 4 albinism patients from this pedigree were analyzed. RESULTS: Sequencing results showed that the proband's TYR gene (NM_000372) has c.230G>A (p.Arg77Gln) and c.120_121insG (p.Asp42GlyfsTer35) compound heterozygous variants. The proband's father carries c.230G>A heterozygous variant, and the mother carries c.120_121insG heterozygous variant, indicating that the proband's two variants are from his father and mother. The former is a known missense variant, which can cause abnormal or loss of the original function of the protein polypeptide chain. The latter c.120_121insG(p.Asp42GlyfsTer35) is an unreported frameshift variant of the TYR gene subregion (EX1; CDS1). PolyPhen-2, SIFT, MutationTaster and FATHMM predictions are all prompted as "harmful variants". This variant caused the amino acid encoded protein to terminate prematurely, producing a truncated protein, which eventually formed a 76-amino acid short-type TYR protein instead of the 529-amino acid wild-type TYR protein. Through the pedigree analysis, the four patients in the pedigree are all of the same type of compound heterozygous variants, and the disease-causing genes are all from the patient's parents. They belong to a special form of consanguineous marriage within 5 generations. CONCLUSION The compound heterozygous variants of c.230G>A (p.Arg77Gln) and c.120_121insG (p.Asp42GlyfsTer35) of the TYR gene may underlie the disease in this pedigree. The gene sequencing results enrich the variant spectrum of the TYR gene, and has facilitated molecular diagnosis for the patient.
Albinism, Oculocutaneous/genetics* ; Consanguinity ; Heterozygote ; Humans ; Mutation ; Pedigree

OBJECTIVE: To analyze the clinical presentation and gene of 2 pedigrees with suspected oculocutaneous albinism(OCA), and provide basis for clinical classification, genetic counseling and prenatal diagnosis. METHODS: Variants were identified using next-generation sequencing(NGS) and confirmed by Sanger sequencing in 2 pedigrees with suspected OCA. The pathogenicity of the variants was analyzed according to the American College of Medical Genetics and Genomics (ACMG) standard. RESULTS: Two compound heterozygous mutations of TYR and OCA2 genes were identified respectively in 2 pedigrees with suspected OCA. The mutation of c.819+3insATATGCC in TYR and the mutation of c.1870G>C in OCA2 are first reported in this study. The pathogenicity analysis shows that two novel mutations are likely pathogenic by combination of prediction of SIFT, Polyphen-2 and Human Splicing Finder. CONCLUSION The findings of this study expand the mutational spectrum of OCA. Compound heterozygous mutations in the TYR and OCA2 gene may be responsible for clinical manifestations of 2 pedigrees with suspected OCA.
Albinism, Oculocutaneous ; DNA Mutational Analysis ; Female ; High-Throughput Nucleotide Sequencing ; Humans ; Membrane Transport Proteins ; Monophenol Monooxygenase ; Mutation ; Pedigree ; Pregnancy

OBJECTIVETo explore the clinical and genetic features of a Chinese boy with oculocutaneous albinism.

METHODSThe clinical features of the patient were analyzed. The DNA of the patient and his parents was extracted and sequenced by next generation exome capture sequencing. The nature and impact of detected mutation were predicted and validated.

RESULTSThe child has displayed strabismus, poor vision, nystagmus and brown hair. DNA sequencing showed that the patient has carried compound heterozygous mutations of the TYRP1 gene, namely c.1214C>A (p.T405N) and c.1333dupG, which were inherited from his mother and father, respectively. Neither mutation was reported previously.

CONCLUSIONThe child has suffered from oculocutaneous albinism type Ⅲ caused by mutations of the TYRP1 gene.

Albinism, Oculocutaneous ; diagnosis ; genetics ; Amino Acid Sequence ; Base Sequence ; Child, Preschool ; Exome ; genetics ; Family Health ; Female ; Heterozygote ; High-Throughput Nucleotide Sequencing ; methods ; Humans ; Male ; Membrane Glycoproteins ; genetics ; Mutation ; Oxidoreductases ; genetics ; Parents

Oculocutaneous albinism type 2 (OCA2) is an autosomal recessive disorder that results from mutations in the P gene, and has approximately 70% function of melanin biosynthesis in the melanocytes. While the overwhelming majority of pigmentation studies have focused on European populations, very little is known about the gene and mechanisms affecting skin lightening in Asian population. The main goal of the study was to test the distribution of three polymorphisms located in a pigmentation candidate gene, OCA2, in a sample of individuals of Koreans (N=250). The genetic markers were selected for polymorphisms that had an allele frequency difference of at least 30% between East Asian populations and European populations. We investigated Minor Allele Frequencies (MAFs) for each of three polymorphisms within OCA2 and reevaluated the difference of the allele frequency along with populations. MAFs of polymorphisms of OCA2 were presented the different frequency in Korean samples (SNP rs1800414 (His615Arg), A allele=38.8%, rs74653330 (Ala481Thr), A allele=0.8% and rs7497270 (intronic polymorphism), C allele=33.4%). While our results had different distributions to European and Caucasians, they showed similar frequencies with East Asian. This study was to reevaluate the distribution of pigmentation candidate gene in Korean samples, further domestic study will aid in developments of the genetic information on worldwide study.
Albinism, Oculocutaneous ; Asian Continental Ancestry Group ; Gene Frequency ; Genetic Markers ; Humans ; Melanins ; Melanocytes ; Pigmentation ; Polymorphism, Single Nucleotide* ; Skin

Mycosis fungoides presenting with hypopigmented lesions is an uncommon variant, which is usually described among dark-skinned patients. We report a case of hypopigmented mycosis fungoides in an eight-year-old girl who has responded favorably to narrowband-ultraviolet B therapy. The disease mimics several benign inflammatory skin conditions, hence, a high clinical suspicion is warranted in patients presenting with widespread hypopigmentation.

Human ; Female ; Child ; Albinism, Oculocutaneous ; Hypopigmentation ; Mycosis Fungoides ; Skin ; Lymphoma

OBJECTIVETo detect potential mutations in genes related with non-syndromic oculocutaneous albinism I-IV and ocular albinism type I in two couples who had given births to children with albinism.

METHODSAll exons of the non-syndromic albinism related genes TYR, OCA2, TYRP-1, MITF, SLC45A2 and GPR143 were subjected to deep sequencing. The results were verified with Sanger sequencing.

RESULTSFor the two female carriers, the coding region of the TYR gene was found to harbor a frameshift mutation c.925_926insC, which was also suspected to have been pathogenic. In one of the male partners, a nonsense mutations c.832C>T was found, which was also known to be pathogenic. Another male partner was found to harbor a TYR gene mutation c.346C>T, which was also known to be a pathogenic nonsense mutation.

CONCLUSIONThe coding region of the TYR gene c.925_926insC (p.Thr309ThrfsX9) probably underlies the OCA1 disease phenotype.

Adult ; Albinism, Oculocutaneous ; enzymology ; genetics ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; China ; Exons ; Female ; Frameshift Mutation ; Humans ; Male ; Membrane Glycoproteins ; genetics ; Molecular Sequence Data ; Mutation, Missense ; Oxidoreductases ; genetics ; Pedigree

OBJECTIVETo provide prenatal diagnosis for two families affected with oculocutaneous albinism (OCA), in both of which only 1 pathogenic allele has been identified.

METHODSTo determine the clinical classification of OCA through DNA sequencing for TYR, P, TYRP1 and SLC45A2 genes in combination with phenotype analysis. Prenatal diagnosis was carried out by direct sequencing and intragenic SNPs family-based linkage analysis.

RESULTSIn the first family, only 1 heterozygous mutation c.1255C>T was found in the proband, which was inherited from her mother. Together with its clinical phenotype, the proband was suspected to have OCA2 Screening of amniotic fluid, however, has found no mutation. With family-based linkage analysis, the fetus was deemed to be an OCA2 carrier. In the second family, again only one heterozygous mutation c.1920_1949 del30bp and ins AACA was found in the proband, which was inherited from her father. Together with its clinical phenotype, the proband was suspected to have OCA2. Screening of amniotic fluid has revealed a heterozygous mutation c.1920_1949 del30bp and ins AACA. By family-based linkage analysis, the fetus was deemed to be an OCA2 carrier. Both fetuses had a normal phenotype at birth.

CONCLUSIONPrenatal genetic diagnosis has been provided for the first time for two families affected with OCA, in which only 1 pathogenic mutant allele was detected. The combined mutation detection and SNPs linkage analysis has turned out to be successful.

Albinism, Oculocutaneous ; genetics ; Female ; Genetic Linkage ; Humans ; Male ; Mutation ; Polymorphism, Single Nucleotide ; Prenatal Diagnosis