Familial adrenal insufficiency, achalasia, alacrima, peripheral neuropathy, microcephaly, normal plasma very long chain fatty acids, and normal muscle mitochondrial respiratory chain enzymes

Molecular Analysis of Libyan Families with Allgrove Syndrome: Geographic Expansion of the Ancestral Mutation c.1331+1G>A in North Africa

BACKGROUND/AIMS

Allgrove syndrome is a rare autosomal recessive disorder characterized by alacrima, achalasia, and adrenal insufficiency. It is caused by mutations of the AAAS gene located on chromosome 12q13 encoding the WD-repeat protein ALADIN. The c.1331+1G>A mutation is one of the most common mutations described in the literature and was identified in Tunisian and Algerian populations. Herein, we describe the clinical and genetic profile of two families from Libya in North Africa associated with Allgrove syndrome.

METHODS

Two unrelated families clinically diagnosed with Allgrove syndrome were evaluated for sequence variations in the AAAS gene. Blood samples were collected, and isolated DNA derived from the subjects was amplified. The entire sequence of the AAAS gene was analyzed by PCR-RFLP and direct sequencing.

RESULTS

Molecular analysis revealed the major homozygous mutation (c.1331+1G>A) in all patients. The presence of a major mutation in Tunisia, Algeria and, as discovered in this report, in Libya in patients with Allgrove syndrome suggests the existence of an ancestral mutation and a founder effect in North Africa.

CONCLUSIONS

The findings allow for a fast genetic counseling in North African families with Allgrove syndrome. To the best of our knowledge, this is the first report of Allgrove syndrome in Libya.

Two siblings with triple A syndrome and novel mutation presenting as hereditary polyneuropathy

The clinical and molecular data on triple A syndrome in two siblings (girl 3.5 years and boy 5.5 years at presentation) with early onset of neurological dysfunction are described. Both patients showed delayed developmental milestones and neurological dysfunctions (motor and sensory demyelinating neuropathy, marked hyperreflexia, calves hypothrophy, pes cavus, gait disturbance) in early childhood, when erroneously diagnosed with hereditary polyneuropathy, most likely Charcot-Marie-Tooth disease. After a severe adrenal crisis in the younger sister at the age of 3 years, the older brother aged 5.5 years was also evaluated and latent adrenal insufficiency was discovered. As both of the siblings had alacrima, hyperkeratosis of palms, cutis anserina, and nasal speech, diagnosis of triple A syndrome was considered. Sequencing of the AAAS gene detected a compound heterozygous mutation consisting of a novel mutation p.Ser296Tyr (c.887C>A) in exon 9 and a previously described p.Ser263Pro (c.787T>C) missense mutation in exon 8 in both siblings. In conclusion, triple A syndrome should be considered in patients presenting with early neurological dysfunction and developmental delay. Alacrima as the earliest and most consistent clinical sign should be investigated by Schirmer test. Patients should be regularly tested for adrenal dysfunction to prevent life-threatening adrenal crises.

The molecular basis of adrenocorticotrophin resistance syndrome

Adrenocorticotrophin resistance syndromes comprise familial glucocorticoid deficiency (FGD) and triple A syndrome, which are rare autosomal recessive diseases with distinct clinical features and molecular etiologies. Mutations of melanocortin-2 receptor (MC2R) have been described in segregation with FGD in 25% of patients. More recently melanocortin-2 receptor accessory protein (MRAP), a small single-transmembrane domain protein, was described as an essential protein for the traffic of MC2R and its expression on the plasma membrane. About 20% of FGD patients carry homozygous mutations of MRAP. The ALADIN protein (for alacrima/achalasia/adrenal insufficiency/neurologic disorder) was identified as the molecular basis of triple A syndrome. The elucidation of the genetic basis of the ACTH resistance syndrome has contributed to the better understanding of MC2R function. However, in some patients the molecular etiology is not yet known and awaits further genetic studies.

Allgrove syndrome with features of familial dysautonomia: a novel mutation in the AAAS gene

Allgrove syndrome (or triple-A syndrome) is a rare autosomal recessive disorder characterized by alacrima, achalasia, adrenal insufficiency (glucocorticoid in the majority of cases) and autonomic/neurological abnormalities. This disease is now known to be caused by mutation in the AAAS gene located on chromosome 12q13. Diagnosis should be readily available when the full-blown features are there, but it becomes less apparent when presentation is atypical or in the evolving process. We present a brother and sister (12 and 19 y old, respectively) born to consanguineous parents of Palestinian origin with Allgrove syndrome. The index patient was erroneously diagnosed to be a case of familial dysautonomia before the diagnosis of adrenal insufficiency was made at the age of 7.5 y, while his elder sister had only alacrima from birth and developed achalasia at the age of 15 y. She started to develop early evidence of adrenal disease at the age of 19 y. Both of them had neuroautonomic dysfunction. The diagnosis of Allgrove syndrome was confirmed in these two patients by studying the gene mutation in the family. The sequencing of the AAAS gene in the two patients identified a novel homozygous mutation within intron 5 (IVS5+1G-->A). Both parents as well as all three other children were heterozygous for the same mutation.

CONCLUSION

These two cases illustrate the heterogenous nature and the intrafamilial phenotypic variability of Allgrove syndrome.

The nuclear pore complex: disease associations and functional correlations

Nuclear pore complexes (NPCs) are large protein structures spanning the double membrane of the eukaryotic nucleus that serve as sites for translocation of macromolecules between the nucleus and the cytoplasm. The vertebrate NPC has recently been found to comprise approximately 30 distinct proteins, collectively referred to as nucleoporins. Studies over the past several years have demonstrated that individual nucleoporins have unique roles in regulating NPC function and the nucleocytoplasmic transport of proteins and RNAs. The unique functions of individual nucleoporins have been made most clear through their associations with specific human diseases. Here, we highlight the relationships between individual nucleoporins and disease, with particular emphasis given to ALADIN, a nucleoporin linked to a genetically heritable human disease known as triple A syndrome.

Chromosomal fragility in patients with triple A syndrome

Triple A syndrome is a rare, autosomal recessive disorder characterized by alacrima, achalasia, and adrenal insufficiency. Previous studies have shown that the triple A gene (AAAS) maps to chromosomal band 12q13. Mutations in the AAAS gene have been identified in triple A syndrome patients; however, the function of this gene is still obscure. We used classical and high-resolution chromosome analyses along with chromosome painting and DNA sequencing to study patients with triple A syndrome. We observed abnormalities in the heterochromatic region of chromosome 9 that included chromatid breaks, chromosome breaks, whole chromosome arm loss, and marker chromosomes, which occurred at unusually high frequencies in affected patients and heterozygotes. Our study raises the possibility of an association between chromosomal fragility in band 9q12 and triple A syndrome. Further investigation is necessary to understand the biologic basis of this finding in the context of triple A syndrome.

Periventricular brain heterotopias in a child with adrenocortical insufficiency, achalasia, alacrima, and neurologic abnormalities (Allgrove syndrome)

We describe a previously unreported finding of periventricular heterotopias in a brain magnetic resonance imaging (MRI) study, in a girl with adrenocortical insufficiency, alacrima, achalasia, and neurologic deterioration (Allgrove syndrome). This finding could indicate that the underlying mechanism in this syndrome can be traced to the first half of fetal life and also might cause abnormal neuronal migration. This disorder recently has been linked to chromosome 12q13. There could be several explanations for the clinical heterogeneity in this syndrome: a contiguous gene syndrome involving multiple genes, including one whose deletion causes heterotopias, or a deficiency of a gene for a neurotrophic factor active during pre- and postnatal life and responsible for both migration and survival of neurons could be the cause. The identification of the responsible gene(s) will lead to further understanding of this multisystem disorder.

Five SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin (SMARC) genes are dispersed in the human genome

The SWI/SNF-related, matrix-associated, actin-dependent regulators of chromatin (SMARC), also called BRG1-associated factors, are components of human SWI/SNF-like chromatin-remodeling protein complexes. We mapped five human SMARC genes toregions on four different human chromosomes, SMARCC1 to 3p23-p21, SMARCC2 to 12q13-q14, SMARCD1 to 12q13-q14, SMARCD2 to 17q23-q24, and SMARCD3 to 7q35-q36. SMARCC1, SMARCC2, and SMARCD1 are assigned to chromosomal regions that are frequently involved in somatic rearrangements in human cancers. SMARCD1 was mapped to the critical region of Allgrove syndrome; however, no mutation was identified in one Allgrove syndrome family studied.

Keratoconjunctivitis sicca associated with achalasia of the cardia, adrenocortical insufficiency, and lacrimal gland degeneration: Keratoconjunctivitis sicca secondary to lacrimal gland degeneration may parallel degenerative changes in esophageal and adrenocortical function

OBJECTIVE/DESIGN

This study aimed to examine and describe three siblings with alacrima, the eldest of whom had associated achalasia and adrenocortical insufficiency.

PARTICIPANTS

Three affected siblings and four age-matched control subjects participated. INTERVENTION/MAIN OUTCOME MEASURES: The three children underwent complete ophthalmologic examinations; computed tomographic scanning of brain, orbit, chest, and abdomen; and measurement of serum cortisol. All three were subjected to a short synacthen challenge. Lacrimal gland biopsies were performed on the two younger subjects, and specimens were studied by light and electron microscopy.

RESULTS

All three children showed virtually absent tear secretion as tested by the Schirmer test. The resulting keratopathy was most severe in the oldest child, who developed bilateral corneal melting. The two younger children showed interpalpebral corneal staining with rose bengal. All three children improved after punctal occlusion. Addison's disease was present in the oldest child. Computed tomographic scanning showed absent lacrimal and shrunken adrenal glands in association with achalasia of the cardia in the oldest child. The lacrimal glands were found to be reduced in size in the next eldest child. When evaluated by electron microscopy, the lacrimal gland biopsy specimens from the two younger children showed neuronal degeneration associated with depletion of secretory granules in the acinar cells.

CONCLUSION

In this disease, radiologic evidence of reducing lacrimal gland size with increasing age could represent a degenerative process. This may be paralleled by other signs and the possibility of adrenocortical insufficiency and achalasia of the cardia should be investigated in all children presenting with dry eyes. These children appear to have a progressive neuronal disease.

Four siblings with achalasia, alacrimia and neurological abnormalities in a consanguineous family

Four siblings with achalasia, alacrimia and other problems involving the autonomic nervous system involvements are reported. Achalasia and alacrimia were present in all of them. Their parents are first cousins and have four other healthy children. Electrophysiological tests showed that autonomic dysfunction has progressed with age. Blood cortisol levels were normal in all four affected children. Depending on those findings of our case and previous reports, we conclude that triple-A syndrome and achalasia, alacrimia with or without neurological abnormalities could be variable manifestations of the same autosomal recessive gene defect.