What is the threshold of mature oocytes to obtain at least one healthy transferable cleavage-stage embryo after preimplantation genetic testing for fragile X syndrome?

PGT-M for Premature Ovarian Failure Related to CGG Repeat Expansion of the FMR1 Gene

Primary ovarian failure (POF) is caused by follicle exhaustion and is associated with menstrual irregularities and elevated gonadotropin levels, which lead to infertility before the age of 40 years. The etiology of POI is mostly unknown, but a heterogeneous genetic and familial background can be identified in a subset of cases. Abnormalities in the fragile X mental retardation 1 gene (FMR1) are among the most prevalent monogenic causes of POI. These abnormalities are caused by the expansion of an unstable CGG repeat in the 5' untranslated region of FMR1. Expansions over 200 repeats cause fragile X syndrome (FXS), whereas expansions between 55 and 200 CGG repeats, which are defined as a fragile X premutation, have been associated with premature ovarian failure type 1 (POF1) in heterozygous females. Preimplantation genetic testing for monogenic diseases (PGT-M) can be proposed when the female carries a premutation or a full mutation. In this narrative review, we aim to recapitulate the clinical and molecular features of POF1 and their implications in the context of PGT-M.

Bohring-Opitz syndrome caused by a novel ASXL1 mutation (c.3762delT) in an IVF baby: A case report

RATIONALE

Bohring-Opitz syndrome is a severe congenital disorder associated with a de novo mutation in the additional sex combs-like 1 (ASXL1) gene, and it is characterized by symptoms that include developmental delay and musculoskeletal and neurological features.

PATIENT CONCERNS

The patient was a girl, an in vitro fertilization (IVF) baby, with delayed motor development, drooling, short stature, slow growth, low muscle tone, image diagnosis of hypoplasia of the corpus callosum, delayed tooth eruption, high palatal arch, adduction of the thumb, drooling, not chewing, excessive joint activity, and ligament relaxation.

DIAGNOSIS

Whole-exome sequencing analysis detected 1 novel disruptive frameshift mutation in ASXL1 in the proband but wild-type ASXL1 in both parents.

INTERVENTIONS

Approximately 1 year of rehabilitation training, which included exercise therapy, toy imitation operation, cognition of daily objects, daily living skills training, gesture language training, oral muscle training, and hand movement training.

OUTCOMES

After approximately 1 year of training, the patient was 3 years old and able to eat normally without drooling. She was able to grasp objects and pick them up after they fell. She was able to grasp small objects and actively played with toys. In addition, she was able to crawl on the floor (at slow speed, with poor initiative), stand with assistance, and walk with assistance; she was unstable when standing unassisted (standing unassisted for 8 seconds at most during training).

LESSON

ASXL1 c.3762delT is a novel mutation that may be caused by IVF. This finding suggests that appropriate gene mutation detection approaches may be necessary for IVF technology.