Progeria in siblings

Skeletal muscle contractile function and neuromuscular performance in Zmpste24 -/- mice, a murine model of human progeria

Human progeroid syndromes and premature aging mouse models present as segmental, accelerated aging because some tissues and not others are affected. Skeletal muscle is detrimentally changed by normal aging but whether it is an affected tissue in progeria has not been resolved. We hypothesized that mice which mimic Hutchinson-Gilford progeria syndrome would exhibit age-related alterations of skeletal muscle. Zmpste24 (-/-) and Zmpste24 (+/+) littermates were assessed for skeletal muscle functions, histo-morphological characteristics, and ankle joint mechanics. Twenty-four-hour active time, ambulation, grip strength, and whole body tension were evaluated as markers of neuromuscular performance, each of which was at least 33% lower in Zmpste24 (-/-) mice compared with littermates (p < 0.06). Contractile capacity of the posterior leg muscles were not affected in Zmpste24 (-/-) mice, but muscles of the anterior leg were 30-90% weaker than those of Zmpste24 (+/+) mice (p < 0.01). Leg muscles were 32-47% smaller in the Zmpste24 (-/-) mice and contained ~60% greater collagen relative to littermates (p < 0.01). Soleus and extensor digitorum longus muscles of Zmpste24 (-/-) mice had excessive myonuclei and altered fiber size distributions but, otherwise, appeared normal. Ankle range of motion was 70% lower and plantar- and dorsiflexion passive torques were nearly 3-fold greater in Zmpste24 (-/-) than Zmpste24 (+/+) mice (p ≤ 0.01). The combined factors of muscle atrophy, collagen accumulation, and perturbed joint mechanics likely contributed to poor neuromuscular performance and selective muscle weakness displayed by Zmpste24 (-/-)mice. In summary, these characteristics are similar to those of aged mice indicating accelerated aging of skeletal muscle in progeria.

Hutchinson-Gilford progeria syndrome: review of the phenotype

Hutchinson-Gilford progeria syndrome (HGPS) is a rare but well known entity characterized by extreme short stature, low body weight, early loss of hair, lipodystrophy, scleroderma, decreased joint mobility, osteolysis, and facial features that resemble aged persons. Cardiovascular compromise leads to early demise. Cognitive development is normal. Data on 10 of our own cases and 132 cases from literature are presented. The incidence in the last century in the Netherlands was 1:4,000,000. Sex ratio was 1.2:1. Main first symptoms were failure to thrive (55%), hair loss (40%), skin problems (28%), and lipodystrophy (20%). Mean age at diagnosis was 2.9 years. Growth in weight was more disturbed than growth in height, and growth delay started already prenatally. Mean height > 13 years was 109.0 cm, mean weight was 14.5 kg. Osteolysis was wide-spread but not expressed, except in the viscerocranium, and remained limited to membranous formed bone. Lipodystrophy is generalized, only intra-abdominal fat depositions remain present. Cardiovascular problems are extremely variable, both in age of onset and nature. Stroke and coronary dysfunctioning are most frequent. Pathologic findings in coronaries and aorta resemble sometimes the findings in elderly persons, but can also be much more limited. Loss of smooth muscle cells seems the most important finding. Mean age of demise was 12.6 years. Patients can be subdivided in patients with classical HGPS, which follows an autosomal dominant pattern of inheritance, (almost) all cases representing spontaneous mutations, and in non-classical progeria, in whom growth can be less retarded, scalp hair remains present for a longer time, lipodystrophy is more slowly progressive, osteolysis is more expressed except in the face, and survival well into adulthood is not uncommon. Pattern of inheritance of non-classical progeria is most probably autosomal recessive. The cause of HGPS is an abnormally formed Lamin A, either directly by a mutated LMNA gene, or through abnormal posttranslational processing (ZMPSTE24 gene mutations). Of 34 LMNA mutations found in progeria patients, there were 26 classical p.G608G mutations (76%). Pathogenesis is most likely to follow several different pathways. Potential therapeutic strategies are developed along these lines and include RNA interference techniques and inhibition of the dominant-negative influence of abnormally formed Lamin A on polymerization with normally formed Lamin A.

A homozygousZMPSTE24null mutation in combination with a heterozygous mutation in theLMNAgene causes Hutchinson-Gilford progeria syndrome (HGPS): insights into the pathophysiology of HGPS

Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder normally caused by a spontaneous heterozygous mutation in the LMNA gene that codes for the nuclear lamina protein lamin A. Several enzymes are involved in the processing of its precursor, prelamin A, to the mature lamin A. A functional knockout of one of the enzymes involved in prelamin A processing, the zinc metalloprotease ZMPSTE24, causes an even more severe disorder with early neonatal death described as restrictive dermatopathy (RD). This work describes a HGPS patient with a combined defect of a homozygous loss-of-function mutation in the ZMPSTE24 gene and a heterozygous mutation in the LMNA gene that results in a C-terminal elongation of the final lamin A. Whereas the loss of function mutation of ZMPSTE24 normally results in lethal RD, the truncation of LMNA seems to be a salvage alteration alleviating the clinical picture to the HGPS phenotype. The mutations of our patient indicate that farnesylated prelamin A is the deleterious agent leading to the HGPS phenotype, which gives further insights into the pathophysiology of the disorder.

A case of mandibuloacral dysplasia presenting with features of scleroderma

Juvenile scleroderma, a relatively rare condition, may be confused with a number of progeroid syndromes like Hutchinson-Gilford syndrome, Werner syndrome and Rothmund-Thomson syndrome. In this case report, we describe a 9-year-old boy who presented with sclerodactyly, acroosteolysis and scleroderma-like involvement of the skin over hands and feet, which suggested a diagnosis of juvenile scleroderma initially. However, absence of Raynaud's phenomenon, sparing of the skin other than hands and feet and negative serological studies did not support this diagnosis. On the basis of additional findings (micrognathia, dental malformation, a 'beaked nose', open cranial sutures and sparse hair), the patient was diagnosed as mandibuloacral dysplasia, a rare autosomal recessive disease. This case demonstrates that mandibuloacral dysplasia should be considered in the differential diagnosis of juvenile scleroderma in the presence of atypical features such as negative serological studies, absence of Raynaud's phenomenon, sparse hair and micrognathia.

Severe bone changes in a case of Hutchinson-Gilford syndrome

The Hutchinson-Gilford progeria syndrome (HGPS) is a very rare, but well known inherited condition of uncertain etiology in which features of premature and accelerated aging are mixed with those of delayed maturity and immaturity. Appearance at birth and birth weight are usually normal but growth typically slows after 1 year. All organ systems undergo degeneration to such an extent that the patient resembles an old man or woman. Short stature, micrognatia, alopecia, sculptured nose, prominent scalp veins, loss of subcutaneous fat, prominent joints, hyperlipidemia and early arteriosclerosis characterize the syndrome. Skeletal compromise includes hypoplasia and dysplasia, persistent open fontanelles, severe osteolysis and pathological fractures. There are no intellectual deficits in patients with this syndrome, and intelligence is unaffected. The life span in progeria is shortened by early arteriosclerosis. In this case, we review the characteristics of the severe osteolytic compromise in distal arms and limbs and bone deformities in a case of an 8-year-old girl, who was admitted to our hospital with short stature and loss of hair. On examination, the child had the major clinical criteria for HGPS as well as severe alterations in osteogenesis, including craniofacial disproportion, short and sculptured nose, delayed dentition, severe scoliosis, clavicular deformity and asymmetrical and hypoplastic arms and legs. Generalized osteopenia and severe osteolytic compromise in distal extremities were found by X-ray examination. In summary, we report the case of an 8-year-old girl who meets the diagnostic criteria for HGPS with severe involvement of her bones and joints with a review of the current literature and a possible therapeutic approach.

Hutchinson-Gilford progeria: familial occurrence

We report on 2 brothers with Hutchinson-Gilford progeria. These patients have 2 unusual findings, i.e., marked resorption of the mandible along with loss of teeth in the elder sib and prolonged survival. Both sibs are still alive and active at the age of 32 and 24 years.

The musculoskeletal manifestations of progeria. A literature review

Although a superficial similarity exists between the musculoskeletal disorders associated with natural aging and those of progeria, an in-depth analysis reveals profound differences in the pathophysiology between the two processes. The protean manifestations of progeria can best be explained on the basis of the vascular changes found at autopsy. A disorder of the vascular endothelium may predispose progeric vessels to atherosclerotic changes. The unique musculoskeletal manifestations of progeria arise from the effects of premature atherosclerosis on the vascularized connective tissues.

Human mutations affecting aging--a review

A review of human genetic mutations that affect aging and their potential contribution to help understand normal aging processes is presented. The lifespans of most animal species, including man, have a genetically determined maximum. The lifespan of man appears to have evolved exceedingly rapidly, which suggests that relatively few genes may determine longevity. Analysis of biochemical evolution suggests that the regulation of enzyme levels may underlie most evolutionary changes. There is a wide spectrum of human genetic mutations. Some, such as progeria and Werner's syndrome, produce a phenotype resembling premature aging and may involve genes related to the aging process. Certain human chromosomal abnormalities, such as Down's syndrome, produce an appearance of premature aging and may be due to abnormal gene regulatory mechanisms. Progress in understanding the genetic mechanisms underlying aging is likely to come from elucidation of the molecular defects that result in the premature aging syndromes and from insights gained regarding the regulatory mechanisms governing eukaryotic genetic expression.