Pregnancy outcome in Charcot-Marie-Tooth disease: results of the CMT-NET cohort study in Germany

Background and purpose

Systematic research on the effect of Charcot–Marie–Tooth (CMT) disease on the outcome of pregnancy and conversely the effect of pregnancy on neuropathy is still sparse.

Methods

A clinical cohort study and cross‐sectional study within the German CMT‐NET was conducted between 2016 and 2019. Inclusion criteria were a confirmed diagnosis of CMT and at least one completed pregnancy after 1990. All participants agreed to fill in questionnaires and have their medical files reviewed.

Results

The study group comprised 54 women with a total of 98 pregnancies. The mean age at onset of CMT disease was 12.6 years (range 0–37 years). Fifty (92%) patients had autosomal dominant CMT; two patients each (4%) had X‐linked and autosomal recessive CMT. Forty patients (74%) had a PMP22 gene duplication (CMT1A). Obstetric complications did not differ significantly from a German reference population, neither in the whole group nor in the CMT1A group. Overall there was no increased newborn morbidity and mortality. About one‐third of patients reported exacerbation of CMT disease in or after pregnancy. No adverse effects of anaesthesia were reported. Most participants stressed a positive attitude and awareness of challenges associated with pregnancy. Important issues were assistance and support in caring for the family.

Discussion

In line with findings from our previous study undertaken in the 1990s, there were no increased complication rates for pregnancy and delivery. These results are reassuring for the vast majority of CMT patients and are important for family planning and clinical care.

Biallelic CSGALNACT1-mutations cause a mild skeletal dysplasia

Genetic causes of skeletal disorders are manifold and affect, among others, enzymes of bone and connective tissue synthesis pathways. We present a twelve-year-old boy with a mild skeletal dysplasia, hypermobility of joints and axial malalignment of lower limbs and feet. Exome sequencing revealed a biallelic loss of function mutation in CSGALNACT1, which encodes chondroitin sulfate N-acetylgalactosaminyltransferase 1 and plays a major role in the chondroitin sulfate chain biosynthesis and therefore in the synthesis of glycosaminoglycans. Recently, the first case of a pediatric patient with a mild skeletal dysplasia due to a compound heterozygous large intragenic deletion and a damaging missense variant in CSGALNACT1 was reported. We here identify a second case and the first juvenile patient with a homozygous frameshift variant in CSGALNACT1 which corroborates its role in mild and non-progressive skeletal dysplasia with joint laxity.

[Rational use of genetic tests in internal medicine : Possibilities and limitations of next generation sequencing diagnostics]

BACKGROUND

New methods of molecular genetic diagnostics enable a more comprehensive genetic analysis of patients.

OBJECTIVES

Rational use and benefits of molecular genetic testing in patients with various internal diseases.

METHOD

Evaluation of topic-related literature, discussion of own experiences, as well as consideration of current guidelines.

RESULTS

New genetic tests, such as next generation sequencing (NGS), improve the diagnosis of hereditary diseases; however, the use of this technology also leads to additional findings, which must be carefully considered.

CONCLUSION

The rational use of genetic tests is a benefit for patients and can significantly influence the prevention and treatment of a disease. The increasing complexity of genetic findings requires interdisciplinary approaches involving human genetics, internal medicine, and other disciplines.

NSD1 duplication in Silver-Russell syndrome (SRS): molecular karyotyping in patients with SRS features

Silver-Russell syndrome (SRS) is a growth retardation syndrome characterized by intrauterine and postnatal growth retardation, relative macrocephaly and protruding forehead, body asymmetry and feeding difficulties. Nearly 50% of cases show a hypomethylation in 11p15.5, in 10% maternal uniparental disomy of chromosome 7 is present. A significant number of patients with SRS features also exhibit chromosomal aberrations. We analyzed 43 individuals referred for SRS genetic testing by molecular karyotyping. Pathogenic variants could be detected in five of them, including a NSD1 duplication in 5q35 and a 14q32 microdeletion. NSD1 deletions are detectable in overgrowth disorders (Sotos syndrome and Beckwith-Wiedemann syndrome), whereas NSD1 duplications are associated with growth retardation. The 14q32 deletion is typically associated with Temple syndrome (TS14), but the identification of a patient in our cohort reflects the clinical overlap between TS14 and SRS. As determination of molecular subtypes is the basis for a directed counseling and therapy, the identification of pathogenic variants in >10% of the total cohort of patients referred for SRS testing and in >16% of characteristic individuals with the characteristic SRS phenotype confirms the need to apply molecular karyotyping in this cohort.

Diagnostic algorithms in Charcot-Marie-Tooth neuropathies: experiences from a German genetic laboratory on the basis of 1206 index patients

We present clinical features and genetic results of 1206 index patients and 124 affected relatives who were referred for genetic testing of Charcot-Marie-Tooth (CMT) neuropathy at the laboratory in Aachen between 2001 and 2012. Genetic detection rates were 56% in demyelinating CMT (71% of autosomal dominant (AD) CMT1/CMTX), and 17% in axonal CMT (24% of AD CMT2/CMTX). Three genetic defects (PMP22 duplication/deletion, GJB1/Cx32 or MPZ/P0 mutation) were responsible for 89.3% of demyelinating CMT index patients in whom a genetic diagnosis was achieved, and the diagnostic yield of the three main genetic defects in axonal CMT (GJB1/Cx32, MFN2, MPZ/P0 mutations) was 84.2%. De novo mutations were detected in 1.3% of PMP22 duplication, 25% of MPZ/P0, and none in GJB1/Cx32. Motor nerve conduction velocity was uniformly <38 m/s in median or ulnar nerves in PMP22 duplication, >40 m/s in MFN2, and more variable in GJB1/Cx32, MPZ/P0 mutations. Patients with CMT2A showed a broad clinical severity regardless of the type or position of the MFN2 mutation. Out of 75 patients, 8 patients (11%) with PMP22 deletions were categorized as CMT1 or CMT2. Diagnostic algorithms are still useful for cost-efficient mutation detection and for the interpretation of large-scale genetic data made available by next generation sequencing strategies.

Chondrosarcoma of bone: an oncological and functional follow-up study

We retrospectively analysed the course of 42 out of 45 patients suffering from different chondrosarcomas which were treated surgically. We found a prospective 5- and 10-year survival of 64% for both time intervals. Follow-up examination was possible in 21 of 45 patients. Most of them were staged as NED, one as AWD, and 8 of 45 were lost to follow-up. From 16 dead patients 12 died of the disease and 4 of unknown but not to tumor related reasons. Survival was depending significantly on the histopathological grade, and the stage according to Enneking's surgical staging system. Eleven out of forty-five patients developed metastases within a mean period of twelve months after surgery. The survival of these patients was significantly reduced. Patients with centrally located tumors exhibited a distinct but non-significant worse survival than those suffering from peripheral tumors. In 18% (8 of 45) recurrence of the tumor was evident within a mean period of 24 months (5-85). Functional evaluation was performed in 21 out of 28 alive patients. After a mean follow-up time of 72 months the mean score was 64% (23-100). Females exhibited a distinct but non-significant better result, the same was observed for peripheral locations compared to centrally located tumors. Regarding age, grade, and line of resection no tendency of any dependence was detected, but worst results were seen in those with a stage III tumor and dedifferentiated CS.