Multicore disease in sibs with severe mental retardation, short stature, facial anomalies, hypoplasia of the pituitary fossa, and hypogonadotrophic hypogonadism

Hypogonadism and neurological diseases

Affected patients with hypogonadism have unnaturally low amounts of sex hormones that produce male and female sex characteristics. Males who suffer from this condition lack testosterone, while females fail to produce enough estrogen. Hypogonadism may be present at birth, or it may take effect years later following injury or illness to the sex glands. Hypogonadism has remarkable associations with variable medical disorders; however, it is characterized by a distinctive association with variable neurological disorders: such as epilepsy, ataxia, dysmyelination, nerve muscle disease, movement disorders, mental retardation and deafness. The remarkable neurological diseases with hypogonadism should not basically be regarded as coincidental findings, but possibly related to an intrinsic pathophysiological association.

Multi-minicore Disease

Multi-minicore Disease (MmD) is a recessively inherited neuromuscular disorder characterized by multiple cores on muscle biopsy and clinical features of a congenital myopathy. Prevalence is unknown. Marked clinical variability corresponds to genetic heterogeneity: the most instantly recognizable classic phenotype characterized by spinal rigidity, early scoliosis and respiratory impairment is due to recessive mutations in the selenoprotein N (SEPN1) gene, whereas recessive mutations in the skeletal muscle ryanodine receptor (RYR1) gene have been associated with a wider range of clinical features comprising external ophthalmoplegia, distal weakness and wasting or predominant hip girdle involvement resembling central core disease (CCD). In the latter forms, there may also be a histopathologic continuum with CCD due to dominant RYR1 mutations, reflecting the common genetic background. Pathogenetic mechanisms of RYR1-related MmD are currently not well understood, but likely to involve altered excitability and/or changes in calcium homeoestasis; calcium-binding motifs within the selenoprotein N protein also suggest a possible role in calcium handling. The diagnosis of MmD is based on the presence of suggestive clinical features and multiple cores on muscle biopsy; muscle MRI may aid genetic testing as patterns of selective muscle involvement are distinct depending on the genetic background. Mutational analysis of the RYR1 or the SEPN1 gene may provide genetic confirmation of the diagnosis. Management is mainly supportive and has to address the risk of marked respiratory impairment in SEPN1-related MmD and the possibility of malignant hyperthermia susceptibility in RYR1-related forms. In the majority of patients, weakness is static or only slowly progressive, with the degree of respiratory impairment being the most important prognostic factor.

Cognitive impairment in neuromuscular disorders

Several studies have suggested the presence of central nervous system involvement manifesting as cognitive impairment in diseases traditionally confined to the peripheral nervous system. The aim of this review is to highlight the character of clinical, genetic, neurofunctional, cognitive, and psychiatric deficits in neuromuscular disorders. A high correlation between cognitive features and cerebral protein expression or function is evident in Duchenne muscular dystrophy, myotonic dystrophy (Steinert disease), and mitochondrial encephalomyopathies; direct correlation between tissue-specific protein expression and cognitive deficits is still elusive in certain neuromuscular disorders presenting with or without a cerebral abnormality, such as congenital muscular dystrophies, congenital myopathies, amyotrophic lateral sclerosis, adult polyglucosan body disease, and limb-girdle muscular dystrophies. No clear cognitive deficits have been found in spinal muscular atrophy and facioscapulohumeral dystrophy.

Minicore myopathy in children: a clinical and histopathological study of 19 cases

Minicore myopathy is a congenital myopathy characterized by multifocal areas of degeneration in muscle fibres. Genetic heterogeneity expected on the basis of clinical variability awaits further resolution. We reviewed 19 cases in order to further delineate the phenotype. Marked hypotonia was the predominant presenting feature, with evidence of antenatal onset in 30% of cases. Weakness was most pronounced axially and proximally, often more severely affecting the shoulder girdle. Mild facial involvement was frequent. Varying degrees of scoliosis were obvious in all patients older than 10 years. In addition, two patients who were also the most severely affected had complete external ophthalmoplegia. One patient showed marked distal involvement. Respiratory failure developed in half of all patients after 10 years of age and correlated strongly with the degree of scoliosis. Cardiac involvement occurred mainly secondary to respiratory impairment. The course appeared static in most cases. Loss of independent walking was observed only in one case at the age of 10 years. On ultrasound scan, differential involvement within the quadriceps was documented in several patients. Variability in fibre size, type 1 predominance and atrophy with occasional type 2 hypertrophy were prominent but nonspecific histological changes. Apart from typical minicores, a marked increase in internal nuclei was the most prominent histological feature. With the exception of one family in which two generations were affected, inheritance appeared autosomal-recessive or sporadic in all cases.

Mental retardation, distinct facial changes, short stature, obesity, and hypogonadism: a new X-linked mental retardation syndrome

We describe a 3-year-old boy and his 2 maternal uncles with moderate to severe mental retardation, short stature, mild obesity, hypogonadism, a low total finger ridge count, and a distinctive face characterized by bitemporal narrowness, almond-shaped palperbral fissures, depressed nasal bridge, anteverted nares, short and inverted-V-shaped upper lip, and macrostomia. Two other males in this family who had similar facial anomalies and developmental delay died in early infancy and midchildhood. This apparently new disorder is reminiscent of, but distinct from, the Prader-Willi syndrome, and is likely inherited as an X-linked recessive trait. Preliminary studies with DNA probes are consistent with an X-linked locus and permit exclusion of distal Xp and Xq regions as the site of this mutation.

Pleocore disease. Multi-minicore disease and focal loss of cross striations

We report clinical and morphological data on seven patients with a congenital myopathy as well as data concerning five parents. Classical myopathies such as rod disease, centronuclear myopathy or central core disease could be ruled out. Structural abnormalities of intracellular organelles or particulate inclusions were rare and insignificant. The most prominent and constant features were minicores and focal loss of cross striations, associated with a prevalence of type 1 fibres, increasing with the age at time of biopsy. A carrier state could not be defined in the five examined parents neither on clinical nor on morphological grounds. Although our group of patients could not clinically be distinguished from other congenital myopathies, the combination of the lesions allow their individualization as a subgroup of multicore or minicore disease under the already proposed denomination of pleocore disease [Martin and Busch, abstract in Zentralbl Allg Pathol 124:156 (1980)].