Skin eruption as the presenting sign of Hunter syndrome IIB

A Case of Mucopolysaccharidosis II Caused by a Novel Variant with Skin Linear Hyperpigmented Streaks along Blaschko′s Lines

We report a case of an eight-year-old boy with mucopolysaccharidosis (MPS) II with atypical skin lesions of hyperpigmented streaks along Blaschko′s lines. This case presented with mild symptoms of MPS such as hepatosplenomegaly, joint stiffness, and quite mild bone deformity, which was the reason for the delay in diagnosis until the age of seven years. However, he showed an intellectual disability that did not meet the diagnostic criteria for an attenuated form of MPS II. Iduronate 2-sulfatase activity was reduced. Clinical exome sequencing of DNA from peripheral blood revealed a novel pathogenic missense variant (NM_000202.8(IDS_v001):c.703C>A, p.(Pro235Thr)) in the IDS gene, which was confirmed in the mother with a heterozygous state. His brownish skin lesions differed from the Mongolian blue spots or “pebbling” of the skin that are observed in MPS II.

Differences in MPS I and MPS II Disease Manifestations

Mucopolysaccharidosis (MPS) type I and II are two closely related lysosomal storage diseases associated with disrupted glycosaminoglycan catabolism. In MPS II, the first step of degradation of heparan sulfate (HS) and dermatan sulfate (DS) is blocked by a deficiency in the lysosomal enzyme iduronate 2-sulfatase (IDS), while, in MPS I, blockage of the second step is caused by a deficiency in iduronidase (IDUA). The subsequent accumulation of HS and DS causes lysosomal hypertrophy and an increase in the number of lysosomes in cells, and impacts cellular functions, like cell adhesion, endocytosis, intracellular trafficking of different molecules, intracellular ionic balance, and inflammation. Characteristic phenotypical manifestations of both MPS I and II include skeletal disease, reflected in short stature, inguinal and umbilical hernias, hydrocephalus, hearing loss, coarse facial features, protruded abdomen with hepatosplenomegaly, and neurological involvement with varying functional concerns. However, a few manifestations are disease-specific, including corneal clouding in MPS I, epidermal manifestations in MPS II, and differences in the severity and nature of behavioral concerns. These phenotypic differences appear to be related to different ratios between DS and HS, and their sulfation levels. MPS I is characterized by higher DS/HS levels and lower sulfation levels, while HS levels dominate over DS levels in MPS II and sulfation levels are higher. The high presence of DS in the cornea and its involvement in the arrangement of collagen fibrils potentially causes corneal clouding to be prevalent in MPS I, but not in MPS II. The differences in neurological involvement may be due to the increased HS levels in MPS II, because of the involvement of HS in neuronal development. Current treatment options for patients with MPS II are often restricted to enzyme replacement therapy (ERT). While ERT has beneficial effects on respiratory and cardiopulmonary function and extends the lifespan of the patients, it does not significantly affect CNS manifestations, probably because the enzyme cannot pass the blood-brain barrier at sufficient levels. Many experimental therapies, therefore, aim at delivery of IDS to the CNS in an attempt to prevent neurocognitive decline in the patients.

Diffuse dermal mucinosis secondary to colony-stimulating factor 1 receptor monoclonal antibody treatment: A novel and peculiar drug-induced diffuse cutaneous mucinosis

Colony-stimulating factor 1 receptor (CSF1R) inhibitors represent a new class of immune-modulatory drugs, mostly investigated in clinical trials in different malignant neoplasms. Four patients, diagnosed with recurrent or advanced malignant neoplasm and treated with a combination of anti-programmed death ligand 1 and anti-CSF1R monoclonal antibodies, developed an asymptomatic cutaneous eruption characterized by an ill-defined pseudoedematous to waxy diffuse infiltration with a reticular cobblestone-like pattern. Histopathological examination revealed diffuse mucin deposition involving the superficial and mid-dermis with fragmented and scattered elastic fibers. The exact pathogenic mechanisms implicated in the development of mucin deposits in patients treated with CSF1R inhibitors remain to be elucidated. A reduced degradation and clearance of components of the extracellular matrix by macrophages secondary to CSF1 pathway inhibition may be hypothesized. Shredding and fragmentation of elastic fibers may be a result of the increased accumulation of mucopolysaccharides. This observation illustrates the new spectrum of skin-related toxicities secondary to new targeting therapies. This may contribute to a better understanding of the underlying pathogenic mechanisms in skin diseases characterized by a persistent dermal glycosaminoglycan deposition.

Spectrum of Lysosomal Storage Disorders at Tertiary Centre: Retrospective Case-Record Analysis

Lysosomal storage disorders (LSDs) are relatively common slow progressive inborn error of metabolism encountered by clinicians. This work intends to highlight the more common LSDs, their clinical presentation, outcome, and mutation (wherever feasible) collected from the genetic clinic at tertiary care center in Eastern Uttar Pradesh. The data for analysis were collected retrospectively from genetic records from a follow-up clinic. All cases < 18 years of age were analyzed. Cases with LSDs with confirmed enzyme results were enrolled in this study. Clinical profile, screening test results, and outcome were collected. There were 32 cases including 27 males and 5 females in this cohort: 8 Gaucher disease (GD) patient and 24 non-GD patients. GD (type 1) is the commonest LSD in GD group. Anemia, thrombocytopenia, splenomegaly, and hepatomegaly were the consistent finding in patients with GD (type 1). L483P mutation was reported in two GD patients. One GD patient is on enzyme replacement therapy for 2 years and is currently doing well. The commonest disorders in non-GD were mucopolysaccharidosis (MPS) ( n  = 11), metachromatic leukodystrophy ( n  = 4), I-cell disease ( n  = 3), Niemann-Pick A/B ( n  = 3). MPS-II is the commonest MPS among non-GD group.

Cognitive and adaptive measurement endpoints for clinical trials in mucopolysaccharidoses types I, II, and III: A review of the literature

Sensitive, reliable measurement instruments are critical for the evaluation of disease progression and new treatments that affect the brain in the mucopolysaccharidoses (MPS). MPS I, II, and III have early onset clinical phenotypes that affect the brain during development and result in devastating cognitive decline and ultimately death without treatment. Comparisons of outcomes are hindered by diverse protocols and approaches to assessment including applicability to international trials necessary in rare diseases. We review both cognitive and adaptive measures with the goal of providing evidence to a Delphi panel to come to a consensus about recommendations for clinical trials for various age groups. The results of the consensus panel are reported in an accompanying article. The following data were gathered (from internet resources and from test manuals) for each measure and summarized in the discussion: reliability, validity, date and adequacy of normative data, applicability of the measure's metrics, cross cultural validity including translations and adaptations, feasibility in the MPS population, familiarity to sites, sensitivity to change, and interpretability. If, resulting from this consensus, standard protocols are used for both natural history and treatment studies, patients, their families, and health care providers will benefit from the ability to compare study outcomes.

Cutaneous Manifestations of Mucopolysaccharidoses

Mucopolysaccharidoses (MPSs) are a group of inherited lysosomal storage disorders characterized by deficiencies in specific enzymes involved in the catabolism of glycosaminoglycans (GAGs). These deficiencies cause excessive metabolites to accumulate in multiple organs. There are eight different MPS disorders, contributing to the wide variation in clinical presentation. Depending on the severity and subtype of the disease, some children live normal life spans, while others have a more grim prognosis. Children with MPS can present with neurologic, behavioral, skeletal, cardiovascular, gastrointestinal, or respiratory abnormalities. Cutaneous manifestations are mostly nonspecific and can include coarse facial features, thickened skin, and excessive hair growth. More specific skin findings include ivory-colored "pebbly" papules found in Hunter syndrome and extensive dermal melanocytosis found in Hurler and Hunter syndromes. Early diagnosis of MPS disorders is extremely important to minimize the progression of the disease and for early initiation of appropriate treatment.

A rare case of mucopolysaccharidosis: Hunter syndrome

We report a rare case of Hunter syndrome—mucopolysaccharidosis type II (MPS II) with atypical presentation of mild mental retardation, acrocephalic head without corneal clouding, and multiple skin eruptions along with oral, dental, and radiographic findings. It is a rare syndrome with a very low prevalence of 1:100,000 births and as such the clinician should be aware of this syndrome.

Enzyme replacement therapy (ERT) procedure for mucopolysaccharidosis type II (MPS II) by intraventricular administration (IVA) in murine MPS II

Mucopolysaccharidosis type II (MPS II), or Hunter syndrome, is a lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS) and is characterized by the accumulation of glycosaminoglycans (GAGs). MPS II has been treated by hematopoietic stem cell therapy (HSCT)/enzyme replacement therapy (ERT), but its effectiveness in the central nervous system (CNS) is limited because of poor enzyme uptake across the blood-brain barrier (BBB). To increase the efficacy of ERT in the brain, we tested an intraventricular ERT procedure consisting of repeated administrations of IDS (20 μg/mouse/3 weeks) in IDS-knockout, MPS II model mice. The IDS enzyme activity and the accumulation of total GAGs were measured in mouse brains. The IDS activity was significantly increased, and the accumulation of total GAGs was decreased in the MPS II mouse brains treated with multiple administrations of IDS via intraventricular ERT. Additionally, a high level of IDS enzyme activity was appreciated in other MPS II mouse tissues, such as the liver, spleen, testis and others. A Y-maze was used to test learning and memory after repeated intraventricular ERT with IDS. The IDS-treated mouse groups recovered the capacity for short-term memory and activity. Although large and small vacuoles were found at the margin of the cerebellar Purkinje cells in the disease-control mice, these vacuoles disappeared upon treated with IDS. Loss of vacuoles was also observed in other tissues (liver, kidney and testis). These results demonstrate the possible efficacy of an ERT procedure with intraventricular administration of IDS for the treatment of MPS II.

Hunter syndrome: resolution of extensive typical skin lesions after 9 months of enzyme replacement therapy with idursulfase

A 10-year-old boy with Hunter syndrome and extensive typical skin lesions underwent 9 months of enzyme replacement therapy, after which the skin lesions disappeared. We believe that treatment with idursulfase probably removes the cutaneous storage of glucosaminoglycans in Hunter syndrome.

Clinical Presentation of Mucopolysaccharidosis Type II (Hunter's Syndrome)

We present a rare case of mucopolysaccharidosis (MPS) with a typical presentation of mental retardation and absence of corneal clouding. The purpose of presenting this case report is to highlight the distinctive manifestation of MPS (Hunter's disease) and to provide a concise report of Hunter's disease for medical practitioners with the hope that such information will help identify boys earlier in the course of their disease. This report is of a 7-year-old boy who presented to the children outpatient through a referral with a history of inability to grasp objects, inability to express self, and coarse skin, which started 5 years ago. On examination, he was short statured, with a big head, protruding abdomen, coarse skin, swollen wrist joints, and clubbed fingers. There was mild mental retardation. Investigations revealed mucopolysaccharides in urine ad radiographic findings were in keeping with diagnosis. Based on the clinical features and radiological findings, one can diagnose a case of MPS. However, careful and critical approach is necessary to exactly diagnose the type of MPS as enzymatic studies are not available in most centers.

Scleromyxedema-like Syndrome With Systemic Involvement in a Cat

Scleromyxedema—the generalized form of lichen myxedematosus, a primary mucinosis—is a rare disease in human patients. It is characterized by dermal mucin deposits, increased numbers of fibroblasts, and variable fibrosis in the absence of thyroid disease. It is accompanied in 80% of cases by a monoclonal gammopathy. To date, scleromyxedema with systemic involvement has not been documented in domestic animals. This is the first report of a scleromyxedema-like syndrome in a cat, which had a substantial deposition of mucin in the dermis of the head and paws with a mild gammaglobulinemia of 2.25 g/dl (reference range, 1.39–2.22 g/dl). At necropsy, multiple nodules of connective tissue intermingled with mucin deposits were conspicuous on the surface of thoracic and abdominal organs. Such severe systemic accumulations of mucin have not been reported in human or veterinary medicine.

Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome)

Mucopolysaccharidosis II, also known as Hunter syndrome, is a rare, X-linked disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase, which catalyzes a step in the catabolism of glycosaminoglycans. In patients with mucopolysaccharidosis II, glycosaminoglycans accumulate within tissues and organs, contributing to the signs and symptoms of the disease. Mucopolysaccharidosis II affects multiple organs and physiologic systems and has a variable age of onset and variable rate of progression. Common presenting features include excess urinary glycosaminoglycan excretion, facial dysmorphism, organomegaly, joint stiffness and contractures, pulmonary dysfunction, myocardial enlargement and valvular dysfunction, and neurologic involvement. In patients with neurologic involvement, intelligence is impaired, and death usually occurs in the second decade of life, whereas those patients with minimal or no neurologic involvement may survive into adulthood with normal intellectual development. Enzyme replacement therapy has emerged as a new treatment for mucopolysaccharidosis disorders, including Hunter syndrome. The purpose of this report is to provide a concise review of mucopolysaccharidosis II for practitioners with the hope that such information will help identify affected boys earlier in the course of their disease.

The effect of haematopoietic stem cell transplant on papules with 'pebbly' appearance in Hunter's syndrome

BACKGROUND

Hunter's syndrome is associated with several cutaneous findings. For instance, papules with 'pebbly' appearance are a specific marker for the disease. However, it remains uncertain whether they disappear after haematopoietic stem cell transplant (HSCT).

OBJECTIVES

To investigate the papules with 'pebbly' appearance before and after HSCT in infants with Hunter's syndrome, and to clarify the effect of HSCT on papules.

PATIENTS

We observed five Japanese boys with Hunter's syndrome who had received HSCT at 4-11 years of age.

RESULTS

The post-HSCT physical examinations revealed that papules disappeared completely within 35 days after the transplant with progressive reduction of cutaneous tightness in all the patients. Histochemical findings showed that papules contained a large amount of hyaluronic acid in the extracellular materials of the dermis and sulphated acid mucopolysaccharides in dermal fibroblasts before HSCT.

CONCLUSIONS

These results suggest that papules with a 'pebbly' appearance fade away through the digestion of a large amount of hyaluronic acid in cutaneous tissues by normal tissue histiocytes or enzymes of donor origin at an early stage after HSCT.

Significance of extensive Mongolian spots in Hunter's syndrome

BACKGROUND

The importance of early diagnosis in infants with a mild form of Hunter's syndrome should be emphasized. If applied sufficiently early, haematopoietic stem cell transplantation (HSCT) or recombinant enzyme therapy may improve the prognosis. At present, however, diagnosis of the mild form of Hunter's syndrome tends to be delayed, especially in infants with relatively normal intelligence.

OBJECTIVES

To investigate the occurrence of Mongolian spots in infants with Hunter's syndrome, and to clarify the relationship between the Mongolian spots and Hunter's syndrome clinically and histopathologically.

METHODS

Seven Japanese boys with Hunter's syndrome who had received HSCT at ages 4-11 years were observed. The cutaneous manifestations of Mongolian spots before HSCT were evaluated, and compared with those after HSCT. In two patients, the hyperpigmentation from the Mongolian spots was examined by light and electron microscopy.

RESULTS

Pre-HSCT observation revealed that all the patients had an extensive Mongolian spot. These were present at birth and have shown no signs of resolution during the post-HSCT period. Electron microscopic findings showed that pigment-bearing dermal melanocytes contained many free melanosomes in stage IV. These were surrounded by extracellular sheaths and encircled by elastic fibres.

CONCLUSIONS

Our results indicate a strong clinical correlation between the extensive Mongolian spots and Hunter's syndrome. Ultrastructural findings also clearly suggest that the hyperpigmentation is a long-lasting symptom. The recognition of the extensive Mongolian spots is essential as it may lead to early diagnosis in patients with a mild form of Hunter's syndrome.