The clinical spectrum of the congenital myasthenic syndrome resulting from COL13A1 mutations.

Next generation sequencing techniques were recently used to show mutations in COL13A1 cause synaptic basal lamina-associated congenital myasthenic syndrome type 19. Animal studies showed COL13A1, a synaptic extracellular-matrix protein, is involved in the formation and maintenance of the neuromuscular synapse that appears independent of the Agrin-LRP4-MuSK-DOK7 acetylcholine receptor clustering pathway. Here, we report the phenotypic spectrum of 16 patients from 11 kinships harbouring homozygous or heteroallelic mutations in COL13A1. Clinical presentation was mostly at birth with hypotonia and breathing and feeding difficulties often requiring ventilation and artificial feeding. Respiratory crisis related to recurrent apnoeas, sometimes triggered by chest infections, were common early in life but resolved over time. The predominant pattern of muscle weakness included bilateral ptosis (non-fatigable in adulthood), myopathic facies and marked axial weakness, especially of neck flexion, while limb muscles were less involved. Other features included facial dysmorphism, skeletal abnormalities and mild learning difficulties. All patients tested had results consistent with abnormal neuromuscular transmission. Muscle biopsies were within normal limits or showed non-specific changes. Muscle MRI and serum creatine kinase levels were normal. In keeping with COL13A1 mutations affecting both synaptic structure and presynaptic function, treatment with 3,4-diaminopyridine and salbutamol resulted in motor and respiratory function improvement. In non-treated cases, disease severity and muscle strength improved gradually over time and several adults recovered normal muscle strength in the limbs. In summary, patients with COL13A1 mutations present mostly with severe early-onset myasthenic syndrome with feeding and breathing difficulties. Axial weakness is greater than limb weakness. Disease course improves gradually over time, which could be consistent with the less prominent role of COL13A1 once the neuromuscular junction is mature. This report emphasizes the role of collagens at the human muscle endplate and should facilitate the recognition of this disorder, which can benefit from pharmacological treatment.

A maternally inherited frameshift CDKL5 variant in a male with global developmental delay and late-onset generalized epilepsy.

Pathogenic CDKL5 variants cause an X-linked dominant infantile epileptic encephalopathy, predominantly in females. This condition is characterized by an early-onset severe mixed seizure disorder. We present a maternally inherited frameshift CDKL5 c.2809_2810insA p.(Cys937Ter) variant in a 13-year-old male with severe intellectual disability and late-onset generalized epilepsy. Interestingly, the variant segregation in the family is consistent with an X-linked recessive inheritance pattern, which has not previously been described with this gene. This variant is expected to result in truncation of some CDKL5 transcripts, which could potentially account for the later seizure onset and atypical inheritance pattern. Though the possibility of this variant not being causal cannot be completely excluded, this case adds to the variability of the documented phenotypic profile and to the debate around the role of C-terminus variants in CDKL5-related disease.

Experiences of Women Who Have Had Carrier Testing for Duchenne Muscular Dystrophy and Becker Muscular Dystrophy During Adolescence.

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive degenerative muscular conditions. Carrier testing is available to at-risk females. Though carrier testing is often offered to adolescent females, it raises ethical issues related to autonomy. This study aimed to address the impact of DMD/BMD carrier testing during adolescence, to elucidate what motivates adolescents to seek testing, and to assess the carrier testing experience. Retrospective semi-structured telephone interviews were conducted with 12 women out of 28 initially contacted. Data were coded using thematic analysis. For most (8/12) participants, discovering their carrier status during adolescence appeared to have helped alleviate uncertainty. The majority (9/12) of participants felt that they had made an autonomous decision and most (10/12) seemed to have adjusted well to their test result. Reproductive factors were framed as having been a key motivator prior to testing. However, following testing, participants' views on prenatal diagnosis seemed more closely linked to their lived experience than to their test result. Just over half (7/12) the participants reported having not had the opportunity for genetic counseling prior to testing and after receiving their result, an issue that warrants further consideration.

Genetic modifiers and ascertainment drive variable expressivity of complex disorders.

Variable expressivity of disease-associated variants implies a role for secondary variants that modify clinical features. We assessed the effects of modifier variants towards clinical outcomes of 2,252 individuals with primary variants. Among 132 families with the 16p12.1 deletion, distinct rare and common variant classes conferred risk for specific developmental features, including short tandem repeats for neurological defects and SNVs for microcephaly, while additional disease-associated variants conferred multiple genetic diagnoses. Within disease and population cohorts of 773 individuals with the 16p12.1 deletion, we found opposing effects of secondary variants towards clinical features across ascertainments. Additional analysis of 1,479 probands with other primary variants, such as 16p11.2 deletion and CHD8 variants, and 1,084 without primary variants, showed that phenotypic associations differed by primary variant context and were influenced by synergistic interactions between primary and secondary variants. Our study provides a paradigm to dissect the genomic architecture of complex disorders towards personalized treatment.

Genetic discrimination by insurance companies in Aotearoa New Zealand: experiences and views of health professionals.

AIMS: Genetic discrimination in insurance is a significant clinical, research and consumer issue. Recently, the Australian life insurance industry introduced a partial moratorium on the use of genetic test results. However, in Aotearoa New Zealand, both life and health insurers can still use genetic results legally to discriminate against applicants. We aimed to document experiences and concerns of New Zealand-based health professionals (HPs) around the potential misuse of genetic test results for insurance purposes. METHODS: We administered an online survey to New Zealand HPs who discuss genetic testing with patients, their experiences regarding the use of genetic test results in insurance and views on regulation. RESULTS: Twenty-three New Zealand HPs responded, 15 of whom worked in genetics clinics, representing >60% of the total New Zealand clinical genetics workforce. Eleven respondents reported having patients who experienced adverse outcomes related to insurance based on genetic results. Respondents reported patients sometimes/often delayed (n=11) or refused (n=4) genetic testing due to insurance concerns. Over 80% of those who answered (n=17/21) believe insurers' use of genetic results should be legally regulated. CONCLUSION: New Zealand HPs have concerns about insurance companies using genetic test results in underwriting, including the effect on patients, and strongly believe government legislation is required.

Not just quantity but also quality of language: Cross-cultural comparisons of maternal mental state talk in New Zealand, Australia, and China.

Western mothers use more mental state talk with children than do Chinese mothers (e.g., "think", "like", "happy"). The present study aimed to examine whether Western mothers not only produced a greater amount of mental state talk, but also used a wider range of mental state terms (i.e., greater lexical variety) compared to Chinese mothers. We compared maternal mental state talk in 271 mother-child dyads from New Zealand, Australia and China, and coded both quantity (i.e., frequency) and quality (i.e., type, variety, valence) of mothers' mental state talk to their 2.5- to 5-year-olds. Western mothers produced more talk about cognitions and emotions, as well as modulations of assertions, but a similar amount of desire talk, compared to Chinese mothers, with the same patterns found in the variety of talk. Western mothers produced an overall higher amount of mental state talk and a greater variety of mental state terms, but crucially, still produced more MS talk after controlling for the variety. Neither the amount nor the variety of maternal MS talk was correlated with children's theory of mind. These findings shed light on the diverse ways that mothers construe and describe mental states in different cultures, and highlight the importance of examining different aspects of maternal mental state talk and their impact on children's theory of mind in future longitudinal studies.

Genomic discrimination in New Zealand health and life insurance. AGenDA: Against Genomic Discrimination in Aotearoa.

Nil.

Germline FFPE inherited cancer panel testing in deceased family members: implications for clinical management of unaffected relatives.

Where previously, germline genetic testing in deceased affected relatives was not possible due to the absence of lymphocytic DNA, the North-West-Genomic-Laboratory Hub (NWGLH) has developed and validated next-generation sequencing based gene panels utilising formalin-fixed-paraffin-embedded (FFPE) tissue DNA from deceased individuals. This technology has been utilised in the clinical setting for the management of unaffected relatives seen in the Clinical Genetics Service (CGS). Here we assess the clinical impact. At the time of data collection, the NWGLH had analysed 180 FFPE tissue samples from deceased affected individuals: 134 from breast and/or ovarian cancer cases for germline variants in the BRCA1/BRCA2 genes and 46 from colorectal, gastric, ovarian and endometrial cancer cases for germline variants in a panel of 13 genes implicated in inherited colorectal cancer and gastric cancer conditions. Successful analysis was achieved in 140/180 cases (78%). In total, 29 germline pathogenic/likely pathogenic variants were identified in autosomal dominant cancer predisposition genes where the gene was pertinent to the cancer family history (including BRCA1/BRCA2, the mismatch-repair genes and APC). Of the 180 cases, the impact of the result on clinical management of unaffected relatives was known in 143 cases. Of these, the results in 54 cases (38%) directly impacted the clinical management of relatives seen by the CGS. This included changes to risk assessments, screening recommendations and the availability of predictive genetic testing to unaffected relatives. Our data demonstrate how FFPE testing in deceased relatives is an accurate and informative tool in the clinical management of patients referred to the CGS.