A case of neonatal Netherton syndrome / 中国当代儿科杂志

A male infant, aged 6 days, was admitted to the hospital due to respiratory distress and systemic desquamative rash after birth. The infant presented with erythema and desquamative rash, respiratory failure, recurrent infections, chronic diarrhea, hypernatremic dehydration, and growth retardation. Comprehensive treatment, including anti-infection therapy, intravenous immunoglobulin administration, and skin care, resulted in improvement of the rash, but recurrent infections persisted. Second-generation sequencing revealed a homozygous mutation in the SPINK5 gene, consistent with the pathogenic variation of Netherton syndrome. The family opted for palliative care, and the infant died at the age of 2 months after discharge. This report documents a case of Netherton syndrome caused by the SPINK5 gene mutation in the neonatal period, and highlights multidisciplinary diagnosis and therapy for this condition.

Pharmacogenetic testing improves treatment responses in patients with PLA2R-related membranous nephropathy / 南方医科大学学报

OBJECTIVE@#To evaluate the value of pharmacogenetic testing for improving the efficacy and safety of treatment with cyclosporine, tacrolimus, and cyclophosphamide (CTX) for PLA2R-related membranous nephropathy and for determing individualized and precise treatment plans for the patients.@*METHODS@#A total of 63 patients with PLA2R-related membranous nephropathy hospitalized in the Department of Nephrology at our hospital from January, 2019 to October, 2021 were enrolled in this study. Thirty-three of the patients underwent pharmacogenetic testing before taking the immunosuppressive drugs selected based on the results of genetic screening for sensitive targets, and the other 30 patients were empirically given immunosuppressive drugs according to the guidelines (control group). The clinical efficacy and adverse effects of the immunosuppressive drugs were analyzed for all the patients. The two groups of patients were compared for demographic and biochemical parameters including 24-h urine protein, serum albumin, renal function, and serum anti-phospholipase A2 receptor antibody both before and at 3 months after the beginning of the treatment.@*RESULTS@#Among the 33 patients undergoing pharmacogenetic testing, 51.5% showed a GG genotype for cyclosporine, and 61.6% had an AG genotype for tacrolimus; for CTX, 51.5% of the patients showed a homozygous deletion and 63.6% had an AA genotype. After treatment for 3 months, serum anti-phospholipase A2 receptor antibody, 24-h urine protein, and serum albumin levels were significantly improved in pharmacogenetic testing group as compared with the control group (P < 0.05).@*CONCLUSION@#Individualized and precise administration of immunosuppressive drugs based on pharmacogenetic testing better controls proteinuria and serum antiphospholipase A2 receptor antibodies and increases serum albumin level in patients with PLA2R-related membranous nephropathy.

Detection of pathogenic variants in four patients with globozoospermia / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for 4 patients with globozoospermia.@*METHODS@#Semen and blood samples were collected from the patients for the determination of sperm concentration, viability, survival rate, morphology and acrosome antigen CD46. Meanwhile, DNA was extracted for whole exome sequencing (WES), and candidate variants were validated by Sanger sequencing.@*RESULTS@#All of the four patients were found to harbor variants of the DPY19L2 gene. Patients 1 ~ 3 had homozygous deletions of the DPY19L2 gene. Sanger sequencing confirmed that the DPY19L2 gene in patient 3 was disrupted at a recombination breakpoint area BP2, resulting in nonallelic homologous recombination and complete deletion of the DPY19L2 gene. Patients 2 and 3 respectively harbored novel homozygous deletions of exons 2 ~ 22 and exons 14 ~ 15. Patient 4 harbored heterozygous deletion of the DPY19L2 gene, in addition with a rare homozygous deletion of the 3' UTR region.@*CONCLUSION@#DPY19L2 gene variants probably underlay the globozoospermia in the four patients, which has fit an autosomal recessive pattern of inheritance and the characteristics of genomic diseases.

Serological characteristics and molecular mechanism of an individual with p phenotype / 中华医学遗传学杂志

OBJECTIVE@#To analyze the serological characteristics and molecular mechanism for an individual with p phenotype.@*METHODS@#An individual with p phenotype upon blood group identification at Jiaxing Blood Center in May 2021 was analyzed. ABO, RhD and P1PK blood groups and irregular antibodies in her serum were identified using conventional serological methods. The encoding region of α1, 4-galactosyltransferase gene (A4GALT) encoding P1 and Pk antigens was analyzed by polymerase chain reaction-sequence-based typing (PCR-SBT).@*RESULTS@#The individual was A group, RhD positive and had a p phenotype of the P1PK blood group system. Anti-PP1Pk was discovered in her serum. Sequencing analysis revealed that she has harbored a homozygous c.343A>T variant of the A4GALT gene.@*CONCLUSION@#The homozygous c.343A>T variant of the A4GALT gene probably underlay the p phenotype in this individual.

Clinical characteristics and genetic analysis of three children with Congenital chlorine diarrhea / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics and genetic basis for three children with Congenital chlorine diarrhea (CCD).@*METHODS@#Three children with CCD who attended the Affiliated Children's Hospital of Capital Pediatric Institute from June 2014 to August 2020 were selected as the research subjects. Peripheral blood samples of the three children and their parents were collected for genetic testing. And the results were verified by Sanger sequencing.@*RESULTS@#The clinical manifestations of the three children have included recurrent diarrhea, with various degrees of hypochloremia, hypokalemia and refractory metabolic alkalosis. Genetic testing revealed that the three children have all carried variants of the SLC26A3 gene, including homozygous c.1631T>A (p.I544N) variants, c.2063_1G>T and c.1039G>A (p.A347T) compound heterozygous variants, and c.270_271insAA(p.G91kfs*3) and c.2063_1G>T compound heterozygous variants. Sanger sequencing confirmed that all of the variants were inherited from their parents.@*CONCLUSION@#The variants of the SLC26A3 gene probably underlay the CCD in these children. Above finding has enriched the spectrum of SLC26A3 gene variants.

Holocarboxylase synthetase deficiency induced by HLCS gene mutations: a rare disease study / 中国当代儿科杂志

A boy, aged 16 months, attended the hospital due to head and facial erythema for 15 months and vulva erythema for 10 months with aggravation for 5 days. The boy developed perioral and periocular erythema in the neonatal period and had erythema and papules with desquamation and erosion in the neck, armpit, and trigone of vulva in infancy. Blood gas analysis showed metabolic acidosis; the analysis of amino acid and acylcarnitine profiles for inherited metabolic diseases and the analysis of organic acid in urine suggested multiple carboxylase deficiency; genetic testing showed a homozygous mutation of c.1522C>T(p.R508W) in the HLCS gene. Finally the boy was diagnosed with holocarboxylase synthetase deficiency and achieved a good clinical outcome after oral biotin treatment. This article analyzes the clinical data of a child with holocarboxylase synthetase deficiency and summarizes the etiology, diagnosis, and treatment of this child, so as to provide ideas for clinicians to diagnose this rare disease.

Genetic analysis of a child with developmental disorder and epilepsy due to a homozygous variant of PIGW gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child featuring global developmental disorder with epilepsy.@*METHODS@#A child who had presented at Guangzhou Women and Children's Medical Center in July 2022 was selected as the study subject. Clinical data was collected. Potential variant was detected by whole exome sequencing (WES). Candidate variant was validated by Sanger sequencing and bioinformatic analysis.@*RESULTS@#The child, a three-year-old ethnic Zhuang Chinese girl, had presented with global developmental disorder and epilepsy, for which rehabilitation therapy was ineffective. Genetic testing revealed that she has harbored a homozygous c.821T>C (p.Leu274Pro) missense variant of the PIGW gene, for which both of her parents and sister were heterozygous carriers. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as variant of uncertain significance.@*CONCLUSION@#The homozygous c.821T>C (p.Leu274Pro) variant of the PIGW gene probably underlay the onset of disease in this child. Above finding has enriched the mutational spectrum of the PIGW gene.

Analysis of a patient with early-onset retinitis pigmentosa due to novel variants of CRB1 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient with early-onset retinitis pigmentosa (RP).@*METHODS@#A patient who had presented at the West China Hospital of Sichuan University on March 10, 2020 was selected as the study subject. The patient and his parents were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing and in silico analysis.@*RESULTS@#The patient has featured substantial loss of binocular vision field. Funduscopy revealed characteristic bone spicule-type pigment deposits, as well as attenuated retinal arterioles and pale-appearing optic discs. WES revealed that he has harbored compound missense variants of a RP-associated CRB1 gene, including c.2969T>C (p.Leu990Ser) and c.1816T>C (p.Cys606Arg), which were respectively inherited from his father and mother. Homozygous c.1816T>C (p.Cys606Arg) variant has been identified among RP patients, whilst the c.2969T>C (p.Leu990Ser) variant was unreported previously. Both variants were predicted as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG).@*CONCLUSION@#The novel compound heterozygous variants of the CRB1 gene probably underlay the early-onset RP in this patient. Above finding has enriched the mutational spectrum of the CRB1 gene.

Clinical characteristics and genetic analysis of two children with neonatal severe hyperparathyroidism / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical features and genetic variants in two children with neonatal severe hyperparathyroidism (NSHPT).@*METHODS@#Two children who were diagnosed with NSHPT at the Children's Hospital Affiliated to Xi'an Jiaotong University respectively in August 2019 and April 2022 were selected as the study subjects. Clinical data were collected, and both children were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing.@*RESULTS@#The main clinical features of the two children have included growth delay, hypotonia, hypercalcemia, hypophosphatemia, hyperparathyroid hormonemia, and renal calcium deposition. WES results showed that child 1 has harbored a homozygous c.1378_1G>A splicing variant of the CASR gene, which was unreported previously, whilst child 2 has harbored a homozygous c.2038C>T missense variant of the CASR gene, which was known to be likely pathogenic. Sanger sequencing confirmed that the parents of both children were heterozygous carriers.@*CONCLUSION@#The homozygous c.1378_1G>A and c.2038C>T variants of the CASR gene probably underlay the NSHPT in the two children. Discovery of the c.1378_1G>A variant has enriched the mutational spectrum of the CASR gene.

Results of carrier screening for Spinal muscular atrophy among 35 145 reproductive-aged individuals from Dongguan region / 中华医学遗传学杂志

OBJECTIVE@#To carry out carrier screening for Spinal muscular atrophy (SMA) in reproductive-aged individuals from Dongguan region and determine the carrier frequency of SMN1 gene mutations.@*METHODS@#Reproductive-aged individuals who underwent SMN1 genetic screening at the Dongguan Maternal and Child Health Care Hospital from March 2020 to August 2022 were selected as the study subjects. Deletions of exon 7 and 8 (E7/E8) of the SMN1 gene were detected by real-time fluorescence quantitative PCR (qPCR), and prenatal diagnosis was provided for carrier couples by multiple ligation-dependent probe amplification (MLPA).@*RESULTS@#Among the 35 145 subjects, 635 were found to be carriers of SMN1 E7 deletion (586 with heterozygous E7/E8 deletion, 2 with heterozygous E7 deletion and homozygous E8 deletion, and 47 with sole heterozygous E7 deletion). The carrier frequency was 1.81% (635/35 145), with 1.59% (29/1 821) in males and 1.82% (606/33 324) in females. There was no significant difference between the two genders (χ² = 0.497, P = 0.481). A 29-year-old woman was found to harbor homozygous deletion of SMN1 E7/E8, and was verified to have a SMN1∶SMN2 ratio of [0∶4], none of her three family members with a [0∶4] genotype had clinical symptoms. Eleven carrier couples had accepted prenatal diagnosis, and one fetus was found to have a [0∶4] genotype, and the pregnancy was terminated.@*CONCLUSION@#This study has determined the SMA carrier frequency in Dongguan region for the first time and provided prenatal diagnosis for carrier couples. The data can provide a reference for genetic counseling and prenatal diagnosis, which has important clinical implications for the prevention and control of birth defects associated with SMA.

A recurrent homozygous missense mutation in CCDC103 causes asthenoteratozoospermia due to disorganized dynein arms / 亚洲男科学杂志(英文版)

Asthenoteratozoospermia is one of the most severe types of qualitative sperm defects. Most cases are due to mutations in genes encoding the components of sperm flagella, which have an ultrastructure similar to that of motile cilia. Coiled-coil domain containing 103 (CCDC103) is an outer dynein arm assembly factor, and pathogenic variants of CCDC103 cause primary ciliary dyskinesia (PCD). However, whether CCDC103 pathogenic variants cause severe asthenoteratozoospermia has yet to be determined. Whole-exome sequencing (WES) was performed for two individuals with nonsyndromic asthenoteratozoospermia in a consanguineous family. A homozygous CCDC103 variant segregating recessively with an infertility phenotype was identified (ENST00000035776.2, c.461A>C, p.His154Pro). CCDC103 p.His154Pro was previously reported as a high prevalence mutation causing PCD, though the reproductive phenotype of these PCD individuals is unknown. Transmission electron microscopy (TEM) of affected individuals' spermatozoa showed that the mid-piece was severely damaged with disorganized dynein arms, similar to the abnormal ultrastructure of respiratory ciliary of PCD individuals with the same mutation. Thus, our findings expand the phenotype spectrum of CCDC103 p.His154Pro as a novel pathogenic gene for nonsyndromic asthenospermia.

Biallelic mutations in spermatogenesis and centriole-associated 1 like (SPATC1L) cause acephalic spermatozoa syndrome and male infertility / 亚洲男科学杂志(英文版)

Acephalic spermatozoa syndrome is a rare type of teratozoospermia that severely impairs the reproductive ability of male patients, and genetic defects have been recognized as the main cause of acephalic spermatozoa syndrome. Spermatogenesis and centriole-associated 1 like (SPATC1L) is indispensable for maintaining the integrity of sperm head-to-tail connections in mice, but its roles in human sperm and early embryonic development remain largely unknown. Herein, we conducted whole-exome sequencing (WES) of 22 infertile men with acephalic spermatozoa syndrome. An in silico analysis of the candidate variants was conducted, and WES data analysis was performed using another cohort consisting of 34 patients with acephalic spermatozoa syndrome and 25 control subjects with proven fertility. We identified biallelic mutations in SPATC1L (c.910C>T:p.Arg304Cys and c.994G>T:p.Glu332X) from a patient whose sperm displayed complete acephalia. Both SPATC1L variants are rare and deleterious. SPATC1L is mainly expressed at the head-tail junction of elongating spermatids. Plasmids containing pathogenic variants decreased the level of SPATC1L in vitro. Moreover, none of the patient's four attempts at intracytoplasmic sperm injection (ICSI) resulted in a transplantable embryo, which suggests that SPATC1L defects might affect early embryonic development. In conclusion, this study provides the first identification of SPATC1L as a novel gene for human acephalic spermatozoa syndrome. Furthermore, WES might be applied for patients with acephalic spermatozoa syndrome who exhibit reiterative ICSI failures.

Advance in the diagnosis and treatment of hereditary thrombotic thrombocytopenic purpura / 中华医学遗传学杂志

Congenital thrombotic thrombocytopenic purpura, also known as Upshaw-Schulman syndrome, is a rare autosomal recessive genetic disorder. The main pathogenesis is homozygous or compound heterozygous variants of von Willebrand factor lyase (ADAMTS13) gene mapped to chromosome 9q34, which may result in severe lack of ADAMTS13 which cleaves von Willebrand factor (vWF) multimers in the plasma and increase the risk of microvascular thrombosis, leading to various complications. The advance of research on the pathogenesis of cTTP, recombinant human ADAMTS13 and gene therapy have made breakthroughs which may lead to cure of cTTP. This article has provided a review for the latest progress made in the diagnosis and treatment of cTTP.

Functional characterization of SLC12A1 gene variants in 3 patients with Bartter syndrome type Ⅰ / 中华儿科杂志

Objective: To clarify the molecular basis of patients with Bartter syndrome type I and explore the therapeutic effect of trafficking-defective variations by chemical chaperone 4-Phenylbutyric acid(4-PBA). Methods: The clinical characteristics, laboratory findings and genetic data of 3 patients diagnosed with Bartter syndrome type I who were admitted to Department of Nephrology, Children's Hospital of Nanjing Medical University from 2017 to 2018 were retrospectively analyzed. Wild type and variant SLC12A1 gene constructs were transiently overexpressed in HEK293 cells. Western blotting was used to detect the expression levels of Na+-K+-2Cl-cotransporter(NKCC2) protein. Immunofluorescent staining was applied to investigate the subcellular localization of NKCC2 protein. In addition, the effect of the chemical chaperone 4-PBA on the expression and localization of the SLC12A1 gene variants was investigated. Unpaired t test was used for statistical analysis of 4-PBA treatment. Results: All the 3 patients (2 males and 1 female), aged 3.0, 4.0 and 1.2 years, respectively. All patients had antenatal onset with polyhydramnios and were born prematurely. After birth, all patients presented with hypochlorine alkalosis accompanied by hypokalemia and hyponatremia. Sequencing analysis revealed that the 3 patients were homozygotes or compound heterozygotes for variants in the SLC12A1 gene. In HEK293 cells, the surface expression of NKCC2 in 3 variants (p.L463S, p.L479V, p.507-510del) are all lower than in wild type (0.718±0.039, 0.287±0.081, 0.025±0.156 vs. 1.001±0.028, t=5.92, 8.35, 30.49, all P<0.01). Moreover, the total protein expression of p.L479V and p.507-510del group were all lower than that in wild type group (0.630±0.032, 0.043±0.003 vs. 1.000±0.111, t=3.21, 8.65, all P<0.05). 4-PBA treatment increased the mature protein expression level of the p.L463S and p. L479V group in 4-PBA treatment group are all higher than the untreated group (0.459±0.018 vs. 1.123±0.024, 0.053±0.012 vs. 1.256±0.037, t=2.75, 18.35, all P<0.05). Cytoplasmic retention of the L479V and 507-510del variants were observed by immunofluorescent staining. 4-PBA treatment could rescue a number of NKCC2 L479V variants to the membrane. Conclusions: The 3 SLC12A1 variants cause expression or subcellular localization defects of the protein. The findings that plasma membrane expression and activity can be rescued by 4PBA might help to develop novel therapeutic strategy for Bartter syndrome type Ⅰ.

Development of Kompetitive Allele Specific PCR markers for identification of persimmon varieties using genotyping-by-sequencing

BACKGROUND: Persimmon (Diospyros kaki Thunb.) is the most widely cultivated species of the genus Diospyros. In this study, genetic diversity and variations in persimmon genotypes were investigated using single nucleotide polymorphism (SNP) markers identified by genotyping-by-sequencing (GBS) analysis. RESULTS: Ninety-five persimmon accessions grown in the Pear Research Institute, National Institute Horticultural and Herbal Science, were sequenced using the Illumina Hiseq2500 platform and polymorphic SNPs were detected to develop molecular markers. These reliable SNPs were analyzed using the Kompetitive Allele Specific PCR (KASP) assay to discriminate among persimmon genotypes. GBS generated a total of 447,495,724 trimmed reads, of which 89.7% were raw reads. After demultiplexing and sequence quality trimming, 108,876,644 clean reads were mapped to the reference transcriptome. An average of 1,146,070 genotype reads were mapped. Filtering of raw SNPs in each sample led to selection of a total of 1,725,401 high-quality SNPs. The number of homozygous and heterozygous SNPs ranged from 1,933 to 6,834 and from 846 to 5,927, respectively. CONCLUSIONS: Of the 49 SNPs selected for development of an identification system for persimmons, 15 SNPs were used in the KASP assay to analyze 32 persimmon accessions. These KASP markers discriminated among all accessions.

A Case-Control Study on Receptor Gene Polymorphism and Risk Suffering from Adult Acute Leukemia in Fujian Area / 中国实验血液学杂志

OBJECTIVE@#To investigate the correlation of receptor gene (P2X7, VDR and SLC19A1) polymorphisms with risk suffering from acute leukemia (AL) in Fujian area.@*METHODS@#Ninety-three cases of newly diagnosed AL as AL group and 90 persons not suffered from hematologic and other tumors as control group were selected and used for comparative analysis of receptor gene polymorphisms and risk suffering from AL between case and control groups. The bone marrow and peripheral blood were collected, from which the DNA was extracted. The PCR-RFLP was used to detect 8 SNP sites (P2X7: rs208294, rs2230911, rs3751143; VDR: rs2228570, rs7975232; SLC194A1: rs1051266, rs1131596, rs3788200) of receptor genes related with the environment response, and the genotypes analysis was used to the correlation of receptor gene polymorphisms with risk suffering from adult AL.@*RESULTS@#The unvariate logistic analysis showed that as compared with control group, P2X7 rs208294 T>C mutation and rs3751143 A>C mutation in codominant model, dominant model and over-dominant model were higher in case group, moreover the differences were statistically significant (PA mutation could increase the risk suffering from AL (PC mutation is one of protective factors against adult acute leukemia.

Serological and molecular biological analysis of an individual with para-Bombay blood group due to homozygous c.948C>A variant of FUT1 gene / 中华医学遗传学杂志

OBJECTIVE@#To study the serological, molecular and genetic characteristics of an individual with para-Bombay blood group.@*METHODS@#Serological method was used to detect the presence of A, B, H antigens in red blood cells and saliva, and Sanger sequencing was used to analyze the FUT1 gene of the proband and her family members. Genetic mechanism of the blood group was analyzed by pedigree analysis.@*RESULTS@#Forward and reverse typing of the ABO blood group were inconsistent for the proband. A, B and H antigens were not found on erythrocytes, while B and H antigens were found in saliva, in addition with unexpected antibodies. The proband was found to have a genotype of ABO*B.01/ABO*O.01.04 caused by homozygous variant of c.948C>A (p.Tyr316Ter) of the FUT1 gene.@*CONCLUSION@#A novel para-Bombay blood group was identified, which was due to the missense variant of c.948C>A in the coding region of the FUT1 gene, which has probably resulted in inability to synthesis active H antigen transferase.

Analysis of genetic variants in a case with Rotor syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a patient featuring Rotor syndrome.@*METHODS@#Clinical data of the patient was collected. Whole exome sequencing (WES) based on high-throughput sequencing technology was carried out. Long-interspersed element-1 (LINE-1) insertion in intron 5 of the SLCO1B3 gene was detected by using tri-primer single tube PCR.@*RESULTS@#WES revealed that the patient has carried homozygous c.1738C>T nonsense variants of the SLCO1B1 gene. He was also found to harbor a homozygous insertion of LINE-1 in intron 5 of the SLCO1B3 gene, which has caused skipping of exon 5 or exons 5 to 7 and introduced a stop codon in the SLCO1B3 transcript.@*CONCLUSION@#The homozygous c.1738C>T variant of the SLCO1B1 gene and homozygous insertion of LINE-1 in intron 5 of the SLCO1B3 gene probably underlay the Rotor syndrome in this patient.

Amyloidosis cutis dyschromica due to homozygous variants of the GPNMB gene in a Chinese pedigree / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a Chinese pedigree affected with amyloidosis cutis dyschromica.@*METHODS@#High-throughput sequencing was carried out for the proband. Bioinformatic analysis was used to identify the pathogenic variants. The result was verified by Sanger sequencing.@*RESULTS@#A homozygous nonsense variant c.565C>T (p.Arg189X) of the GPNMB gene was identified in the proband, his elder brother and younger sister, which resulted a truncated protein with loss of function. The father of the proband was a heterozygous carrier for the variant. The genotype of his mother was unknown since she had passed away. Based on the American College of Medical Genetics and Genomics standards and guidelines, the c.565C>T variant was predicted to be likely pathogenic (PS3+ PM2+ PP1+PP3).@*CONCLUSION@#The novel homozygous GPNMB variant probably underlay the amyloidosis cutis dyschromica in this pedigree. Above finding has expanded the spectrum of GPNMB gene variants.

Clinical practice guidelines for the diagnosis of regions of homozygosity and uniparental disomy / 中华医学遗传学杂志

The overall prevalence of uniparental disomy (UPD) across all chromosomes was estimated to be around one birth in 2000. To date, more than 4170 UPD cases have been registered. UPD for chromosomes 6, 7, 11, 14, 15, and 20 can result in clinically recognizable imprinting disorders due to abnormal levels of imprinted gene expression. For other chromosomes, the clinical consequences associated with UPD are not apparent, unless when a recessive genetic disorder is unmasked by UPD or regions of homozygosity (ROH). A clinical practice guideline will assist in strengthening the precise analysis and interpretation of the clinical significance of ROH/UPD. This guideline summarizes the conception, mechanism and clinical consequences of ROH/UPD, as well as the principles for data analysis, with an aim to standardize the clinical application and data interpretation.