China is facing the great challenge of treating the world's largest rare disease population, an estimated 16 million patients with rare diseases. One effort offering promise has been a pilot national project that was launched in 2013 and that focused on 20 representative rare diseases. Another government-supported special research program on rare diseases – the "Rare Diseases Clinical Cohort Study" – was launched in December 2016. According to the plan for this research project, the unified National Rare Diseases Registry System of China will be established as of 2020, and a large-scale cohort study will be conducted from 2016 to 2020. The project plans to develop 109 technical standards, to establish and improve 2 national databases of rare diseases – a multi-center clinical database and a biological sample library, and to conduct studies on more than 50,000 registered cases of 50 different rare diseases. More importantly, this study will be combined with the concept of precision medicine. Chinese population-specific basic information on rare diseases, clinical information, and genomic information will be integrated to create a comprehensive predictive model with a follow-up database system and a model to evaluate prognosis. This will provide the evidence for accurate classification, diagnosis, treatment, and estimation of prognosis for rare diseases in China. Numerous challenges including data standardization, protecting patient privacy, big data processing, and interpretation of genetic information still need to be overcome, but research prospects offer great promise.

Epidermolysis bullosa (EB) is a clinically and genetically heterogeneous group of inherited blistering diseases that affects ~ 500,000 people worldwide. Clinically, individuals with EB have fragile skin and are susceptible to blistering following minimal trauma, with mucous membrane and other organ involvement in some subtypes. Within the spectrum of EB, ~ 5% of affected individuals have the clinically more severe recessive dystrophic (RDEB) variant with a prevalence of 8 per one million of the population. RDEB is caused by loss-of-function mutations in the type VII collagen gene, COL7A1, which leads to reduced or absent type VII collagen (C7) and a paucity of structurally effective anchoring fibrils at the dermal-epidermal junction (DEJ). Currently, there is no cure for RDEB, although considerable progress has been made in testing novel treatments including gene therapy (lentiviral and gamma retroviral vectors for COL7A1 supplementation in keratinocytes and fibroblasts), as well as cell therapy (use of allogeneic fibroblasts, mesenchymal stromal cells (MSCs), and bone marrow transplantation (BMT)). Here, we review current treatment modalities available as well as novel and emerging therapies in the treatment of RDEB. Clinical trials of new translational therapies in RDEB offer hope for improved clinical management of patients as well as generating broader lessons for regenerative medicine that could be applicable to other inherited or acquired abnormalities of wound healing or scarring.

Pancreatic neuroendocrine neoplasms (pNENs) are a heterogeneous group of tumors including well differentiated pancreatic neuroendocrine tumors (pNETs) and neuroendocrine carcinomas (pNECs). The incidence of pNENs has increased over the past few decades. Although, the understanding and interest for this tumor have also increased significantly, the debate about classification and diagnosis continues. Although the primary treatment for pNENs is surgical resection, there is still a lack of effective therapeutic options for patients with advanced unresectable pNENs. Although many therapeutic methods have proven effective, the choice of treatment and specific programs are still unclear. Our article presents an overview of pNENs, with a focus on their diagnostic work-up, clinical presentation and treatment options.

Phase-1 (also known as "First-in-Man") clinical trials initiate the early clinical development of possible new medicines. Patient participation in this early phase of clinical trials is rather limited. After successful phase 1 trials, further phase 2 and phase 3 clinical trials in patients may lead to a marketing authorization. In the first 15 years of the European Union Orphan Drug Directive, 4.5% of the orphan drug applications were authorized. However, for many of these orphan drugs, no phase 1 studies were required, as these products were already well known pharmaceutical substances, with a clearly defined pharmacological profile. Furthermore, for 19 orphan drugs, already authorized by the European Medicines Agency (EMA), the original rare indication was extended to another rare disease and no phase 1 trials were needed. Phase 1 studies need to be performed in a sufficient number of volunteers even for medicinal products intended for a very limited number of patients.

Interferon-stimulated exonuclease gene 20 (ISG20) is an RNA exonuclease in the yeast RNA exonuclease 4 homolog (REX4) subfamily and the DEDDh exonuclease family, and this gene codes for a 20-kDa protein. Those exonucleases are involved in cleaving single-stranded RNA and DNA. ISG20 is also referred to as HEM45 (HeLa estrogen-modulated, band 45). Expression of ISG20 can be induced or regulated by both type I and II interferons (IFNs) in various cell lines. ISG20 plays a role in mediating interferon's antiviral activities. In addition, ISG20 may be a potential susceptibility biomarker or pharmacological target in some inflammatory conditions. Exonucleases are useful components of many physiological processes. Despite recent advances in our understanding of the functions of ISG20, much work remains to be done with regard to uncovering the mechanism of action of ISG20 in specific diseases and adapting ISG20 for use as a biomarker of disease. This review describes current information on ISG20 and its potential use in marking disease. This review describes several research achievements thus far and it seeks to provide some new ideas for future related research.

Dent disease is a rare X-linked recessive proximal tubular disorder that affects mostly male patients in childhood or early adult life. Dent disease is clinically characterized by the presence of low molecular weight proteinuria (LMWP), hypercalciuria, medullary nephrocalcinosis, nephrolithiasis, and progressive renal failure. The clinical features, diagnosis, and treatment of Dent disease were examined in 10 Chinese boys. All 10 childhood cases of Dent disease in China presented with tubular proteinuria in the nephrotic range and hypercalciuria. The ratio of α1-microglobulinuria to microalbuminuria, if close to or above 1, can be used as a diagnostic criterion for tubuloproteinuria. Lotensin was ineffective at treating proteinuria while dihydrochlorothiazide reduced urine calcium excretion.

The objective of the study was to retrospectively determine the prevalence of vestibular symptoms in individuals with auditory neuropathy spectrum disorder (ANSD). It was also attempted to determine the prevalence of vestibular symptoms and factors (gender and age of reported hearing loss) that could affect the prevalence in individuals with ANSD. The vestibular symptoms reported in the case history were analyzed in individuals diagnosed with ANSD. The symptoms reported by a total of 316 individuals (185 females and 131 males) with ANSD were analyzed. The result of the study showed that one in five individuals with ANSD reported at least one of the vestibular symptom. The vestibular symptoms were in more females and in individuals with earlier onset of hearing loss. The result of the study supports that there is a vestibular damage in individuals with ANSD. However, it is essential to carry out prospective studies validating these vestibular symptoms with objective vestibular tests before generalizing the results.

The G protein-coupled receptor 17 (GPR17), a Gi-coupled GPCR, acts as an intrinsic timer of oligodendrocyte differentiation and myelination. The expression of GPR17 is upregulated during differentiation of oligodendrocyte precursor cells (OPCs) into premyelinating oligodendrocytes (preoligodendrocytes), whereas it is markedly downregulated during terminal maturation of myelinating oligodendrocytes. Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder caused by a loss-of-function mutation of either TYROBP (DAP12) or TREM2. Pathologically, the brains of NHD patients exhibit extensive demyelination designated leukoencephalopathy, astrogliosis, accumulation of axonal spheroids, and activation of microglia predominantly in the white matter of frontal and temporal lobes. Although GPR17 is a key regulator of oligodendrogenesis, a pathological role of GPR17 in NHD brains with relevance to development of leukoencephalopathy remains unknown. We studied the expression of GPR17 in five NHD brains and eight control brains by immunohistochemistry. We identified GPR17-immunoreactive preoligodendrocytes with a multipolar ramified morphology distributed in the white matter and the grey matter of all cases examined. However, we did not find statistically significant differences in the number of GPR17-expressing cells between NHD and control brains both in the white matter and the grey matter due to great variability from case to case. These observations do not support the view that GPR17-positive preoligodendrocytes play a central role in the development of leukoencephalopathy in NHD brains.

An 18-year-old boy presented with acute-onset quadriparesis that had developed 4 weeks prior. He had an intermittent fever and significant weight loss during this period. After extensive investigations, the patient was diagnosed with an acute motor and sensory axonal neuropathy (AMSAN) variant of Guillain-Barre syndrome (GBS) and disseminated tuberculosis with mediastinal lymphadenopathy, pericarditis, and pleural effusion. Plasmapheresis was performed and first-line anti-tubercular therapy was administered. At the follow-up at 6 months, the patient was asymptomatic, he had no residual weakness and could walk without support, and tuberculosis had completely resolved on X-rays. Many infectious agents have been known to trigger GBS, but only a few cases of GBS and tuberculosis have been reported. This association needs to be evaluated further.

Gomez-Lopez-Hernández syndrome (GLHS) is a rare neurocutaneous syndrome char- acterized by a triad of findings: partial alopecia of the scalp, trigeminal anaesthesia, and rhombencephalosynapsis. GLHS is also known as cerebello-trigeminal- dermal dysplasia. Besides this triad, a number of varying traits have been described in 35 previously reported cases. Reported here is a case of a four-year-old boy, born out of consanguine-ous marriage, presenting with the classic triad of findings, i.e. partial alopecia of the scalp, trigeminal anaesthesia, and rhombencephalosynapsis. To the extent known, this is the first case of GLHS reported from India. If a child presents with alopecia and rhom-bencephalosynapsis, GLHS should be considered in the differential diagnosis. A host of studies can be used to determine the exact pathogenesis, and confirming the diagnosis of GLHS is an important step in prenatal testing for at-risk pregnancies.

Reported here are twins, both of whom have a 1q21.3 microdeletion and who exhibit key features common to previously reported cases such as microcephaly and developmental delay. However, some clinical findings and deleted genes differed from those in previously reported cases. The karyotype was normal 46, XX for both of the twins. Array comparative genomic hybridization (CGH) identified a 2.6 Mb deletion on chromosome 1q21.3 (chr1: 153,514,121-156,171,335 bp) in case 1 and a 1.6 Mb deletion on chromosome 1q21.3 (chr1: 154,748,365- 156,358,923 bp) in case 2. The deleted region includes DPM3, MUC1, GBA, PKLR, RIT1, and LAMTOR2 in both siblings. To the extent known, this is the second report of a 1q21.3 microdeletion in a family with mental retardation, developmental delay, seizures, and some dysmorphic features, thus expanding the phenotypic spectrum.

Lesch-Nyhan syndrome (LNS) is an X-linked recessive disorder of purine metabolism caused by a mutation in Xq26.2-q26.3 (OMIM 308000.0004). The presence of the diagnostic triad, i.e. signs of self-injurious behavior (SIB) and results of pedigree analysis and novel molecular biology & genetic testing, confirms the diagnosis of LNS. With a level of hypoxanthine guanine phosphoribosyl-transferase 1 (HPRT1) enzyme activity < 2%, patients develop neurological, neurocognitive, and neuromotor symptoms along with SIB. Described here is a case of 4-year-old boy who was diagnosed with LNS. The boy displayed SIB, i.e. biting of the lips and fingers, and he had cerebral venous sinus thrombosis caused by LNS.

Reported here is a case of upper gastrointestinal bleeding secondary to a peptic ulcer involving an extremely high platelet count of 989 × 10⁹/L. Myeloproliferative neoplasms were ruled out on the basis of gene mutation testing and a bone marrow biopsy. After the cessation of index bleeding, the platelet count decreased markedly. Thus, reactive thrombocytosis was considered as a possibility.

Reported here are audiological findings from an adult with thin cochlear nerves. Magnetic resonance imaging (MRI) revealed that he had a thinner cochlear nerve in the left ear than in the right ear. He had a higher degree of hearing loss in the left ear and poor speech recognition scores for both ears. He had normal middle ear and cochlear functioning. The auditory brainstem response and acoustic reflexes were absent, indicating a retrocochlear pathology. Long latency responses (LLR) revealed normal cortical functioning. Hence, implantation of an auditory brainstem implant might be an option, but the patient would need to be aware of its limitations. This case highlights the importance of MRI in evaluating congenital malformations of the cochlear nerve when audiological findings indicate a retrocochlear pathology.

Griscelli syndrome (GS) is a rare autosomal recessive disorder resulting in pigmentary dilution of the skin and hair with variable phenotypes depending upon subtypes. Mutations in 3 distinct genes MYO5A, RAB27A, MLPH are responsible for 3 subtypes (GS1, GS2, and GS3) of GS respectively. GS subtype 2 commonly develops hemophagocytic lymphohistiocytosis (HLH) and recurrent infections due to immunodeficiency. We hereby report a 20 month old male child presenting with silvery gray hair, hypomelanosis and features of hemophagocytosis. The diagnosis of a type 2 GS was made in response to a set of clinical features: hypopigmentation of skin and the silvered reflection of the hair, absence of psychomotor retardation, the occurrence of an accelerated phase (hemophagocytosis) and, above all, a pathognomonic appearance by microscopic examination of a hair. The absence of giant granules in the nucleated cells made it possible to eliminate Chediak-Higashi syndrome, which shares a close clinical spectrum with GS. This case promotes awareness about this rare case of GS as a high indicator of suspicion about this potentially fatal condition and aids in prompt diagnosis and foresees complications. Early bone marrow transplant is the only curative treatment for GS-2.