Clinical Deep Phenotyping of ABCA7 Mutation Carriers

Background and ObjectivesPutative loss-of-function (pLOF) ABCA7 variants that increase Alzheimer disease (AD) risk were identified; however, deep phenotypic characterization of these variants in mutation carriers is limited. We aimed to obtain deep clinical phenotypes of ABCA7 pLOF mutation carriers from a large retrospectively reviewed series.MethodsGenotypes were determined for 5,353 individuals evaluated at Mayo Clinic for 6 reported ABCA7 pLOF variants (p.E709fs, p.Trp1214X, p.L1403fs, c.4416+2T>G, p.E1679X, and c.5570+5G>C). Medical records of 100 mutation carriers were reviewed for demographics, clinical phenotypes, and diagnoses. Eleven mutation carriers had autopsy-based neuropathologic diagnoses.ResultsWe confirmed that ABCA7 pLOF mutations confer AD risk in our series of 2,495 participants with AD and 2,858 cognitively unaffected participants. Clinical review of 100 mutation carriers demonstrated phenotypic variability of clinical presentations with both memory and nonmemory cognitive impairment and a subset presenting with motor symptoms. There was a wide range of age at onset of cognitive symptoms (ages 56–92 years, mean = 75.6). Ten of the 11 autopsied mutation carriers had AD neuropathology. ABCA7 pLOF mutation carriers had higher rates of depression (41.6%) and first-degree relatives with cognitive impairment (38.1%) compared with the general population.DiscussionOur study provides a deep clinical review of phenotypic characteristics of mutation carriers for 6 ABCA7 pLOF mutations. Although memory impairment was the most common initial symptom, nonmemory cognitive and/or motor symptoms were present in a substantial number of mutation carriers, highlighting the heterogeneity of clinical features associated with these mutations. Likewise, although AD neuropathology is the most common, it is not the only autopsy-based diagnosis. Presence of earlier ages at onset, higher rates of depression, and first-degree relatives with cognitive impairment among mutation carriers suggest that these genetic variants may have more aggressive clinical features than AD in the general population. This deep phenotyping study of ABCA7 pLOF mutation carriers provides essential genotype-phenotype correlations for future precision medicine approaches in the clinical setting.

Pathophysiology of the Different Clinical Phenotypes of Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common form of autoimmune polyneuropathy. It is a chronic disease and may be monophasic, progressive or recurrent with exacerbations and incomplete remissions, causing accumulating disability. In recent years, there has been rapid progress in understanding the background of CIDP, which allowed us to distinguish specific phenotypes of this disease. This in turn allowed us to better understand the mechanism of response or non-response to various forms of therapy. On the basis of a review of the relevant literature, the authors present the current state of knowledge concerning the pathophysiology of the different clinical phenotypes of CIDP as well as ongoing research in this field, with reference to key points of immune-mediated processes involved in the background of CIDP.

Rare genetic variants in dominant developmental disorder loci cause milder related phenotypes in the general population

Many rare diseases are known to be caused by deleterious variants in Mendelian genes, however the same variants can also be found in people without the associated clinical phenotypes. The penetrance of these monogenic variants is generally unknown in the wider population, as they are typically identified in small clinical cohorts of affected individuals and families with highly penetrant variants. Here, we investigated the phenotypic effect of rare, potentially deleterious variants in genes and loci that are known to cause monogenic developmental disorders (DD) in a large population cohort. We used UK Biobank to investigate phenotypes associated with rare protein-truncating and missense variants in 599 dominant DD genes using whole exome sequencing data from ~200,000 individuals, and rare copy number variants overlapping known DD loci using SNP-array data from ~500,000 individuals. We found that individuals with these likely deleterious variants had a mild DD-related phenotype, including lower fluid intelligence, slower reaction times, lower numeric memory scores and longer pairs matching times compared to the rest of the UK Biobank cohort. They were also shorter, with a higher BMI and had significant socioeconomic disadvantages, being less likely to be employed or be able to work, and having a lower income and higher deprivation index. Our findings suggest that many monogenic DD genes routinely tested within paediatric genetics have intermediate penetrance and may cause lifelong milder, sub-clinical phenotypes in the general adult population.

Hyperaldosteronism: types, clinical characteristics, and treatment

Cases with hyperaldosteronism might be asymptomatic in many events. Therefore, the diagnosis can be missed. However, the usual presentation for many patients has been reported to be a refractory elevation in the blood pressure which might be mild to severe. Based on the type of hyperaldosteronism and the diagnosis, the treatment of these conditions should be established. Therefore, it can be concluded that the treatment is specific to the management of the underlying etiology, and managing the clinical characteristics and associated complications. This present literature review aims to provide evidence regarding the types, clinical characteristics, and treatment of aldosterone based on data from the current investigations in the literature. Different clinical phenotypes have been reported for the condition. Nevertheless, the disease can be broadly classified into primary and secondary hyperaldosteronism based on the pathophysiology and etiology of the condition. Clinical characteristics might not be diagnostic since they are very non-specific, despite being common in these patients, as hypokalemia and hypertension. Therefore, clinicians should be aware of conducting the necessary diagnostic approaches before establishing the diagnosis. Management of these patients requires the integration of different approaches, including surgical and medical treatment. Perioperative care is important because it may lead to unfavorable consequences if neglected.