QRICH1 variants in Ververi‐Brady syndrome—delineation of the genotypic and phenotypic spectrum

Ververi‐Brady syndrome (VBS, # 617982) is a rare developmental disorder, and loss‐of‐function variants in QRICH1 were implicated in its etiology. Furthermore, a recognizable phenotype was proposed comprising delayed speech, learning difficulties and dysmorphic signs. Here, we present four unrelated individuals with one known nonsense variant (c.1954C > T; p.[Arg652*]) and three novel de novo QRICH1 variants, respectively. These included two frameshift mutations (c.832_833del; p.(Ser278Leufs*25), c.1812_1813delTG; p.(Glu605Glyfs*25)) and interestingly one missense mutation (c.2207G > A; p.[Ser736Asn]), expanding the mutational spectrum. Enlargement of the cohort by these four individuals contributes to the delineation of the VBS phenotype and suggests expressive speech delay, moderate motor delay, learning difficulties/mild ID, mild microcephaly, short stature and notable social behavior deficits as clinical hallmarks. In addition, one patient presented with nephroblastoma. The possible involvement of QRICH1 in pediatric cancer assumes careful surveillance a key priority for outcome of these patients. Further research and enlargement of cohorts are warranted to learn about the genetic architecture and the phenotypic spectrum in more detail.

Patient 1 was born at 37 weeks of gestation after a pregnancy complicated by preeclampsia and placental insufficiency. Birth measurements were normal (length: 50 cm (+0.21 SD), weight: 3060 g (+0.19 SD), OFC: 33 cm (−0.64 SD)). She displayed temperature dysregulation and feeding difficulties. Milestones of motor development were moderately delayed. She was able to sit at 7 months and to walk without support at age 17 months. Speech was limited to single words at the age of 3 2 / 12 years. She presented with congenital nonprogressive melanocytic nevi and unilateral sensorineural hearing loss. Aged 1.5 years, normal CK level was observed. Aged 1 7 / 12 years, diagnosis of left side high-risk nephroblastoma was established. Despite of nephrectomy and enrollment in the nephroblastoma trial SIOP 2001/GPOH, she deceased at age 3 2 / 12 years due to severe sepsis.

| Patient 2
Patient 2 was the third child of healthy unrelated parents originating from Germany. Family history was unremarkable. (d) tendency to social withdrawal; and (e) childlike behavior patterns.
She attended an integrative school for language therapy. EEG showed unspecific changes with theta-rhythmization without seizures. She had mild scoliosis, slightly accelerated skeletal age. She displayed normal CK levels aged 12 and 19 months. MRI of the brain at age 11 years revealed a small pineal cyst (ø 7.2 mm). On physical examination at age 15 3 / 12 years, weight (53 kg, −0.40 SD), OFC (55.5 cm, +0.52 SD) and height (158 cm, +0.52 SD) were in the normal range. She presented with mild craniofacial dysmorphisms (Figure 1). camptodactyly of the right third finger, carious teeth and atopic dermatitis. EEG at age 4 10 / 12 years showed unspecific changes with theta-rhythmization without seizures. MRI of the brain performed at age 5 5 / 12 years revealed a small pineal cyst (ø 6 mm) and no further anomalies.

| Patient 3
On physical examination at age 5 5 / 12 years, weight (22.3 kg, +0.59 SD), and height (113 cm, −0.32 SD) were in the normal range, whereas OFC (49 cm, −2.23 SD) was decreased. This boy was described with a friendly behavior and mildly dysmorphic features including prominent upper lip and wide mouth.

| Patient 4
This boy was born at gestational week 40 by cesarean section with normal growth parameters (weight: 3090 g, −1.21 SD, length: 51 cm, −0.65 SD, OFC: 35 cm, −0.46 SD). Family history was remarkable as the patient had an older brother with developmental delay.
In the first months, muscular hypotonia was noted. The boy could sit at age 10 months and walk at age 16 to 17 months. Age of first words was reported normal, but then delayed speech development was noted. Testing with the Snijders Oomen Nonverbal Intelligence Test for elderly children and adults (SON-R51/2-17) at age 9 years 7 months revealed an IQ of 78, and he attended a school for children with special needs. As a young adult, he lived and worked in a shel- He had a slender habitus, and minor facial aspects included a long face, large ears, wide palpebral fissures, periorbital fullness, a long philtrum, a high palate and thin lips.
All four patients had normal chromosomal and normal microarray analysis results and normal testing for Fragile-X. In addition, targeted testing for Coffin-Lowry syndrome in patient 4 as well as testing for spinal muscular atrophy (SMA) and congenital muscular dystrophy 1 (CMD) in patient 3 revealed normal results, respectively.

| MOLECULAR RESULTS
In the first patient, trio-based WES identified a de novo heterozygosity for the variant at position QRICH1 NM_017730.3:c.2207G > A; p.
(Ser736Asn). This variant has not been reported before in the dbSNP 8 and gnomAD 9 variant databases (Supplemental Table 2, Supplemental  Table 1, Supplemental Table 2

| DISCUSSION
QRICH1-related neurodevelopmental disorder/VBS is a rare entity.
The mutations identified in QRICH1 so far included de novo nonsense and frameshift mutations and have been suggested to exert their effect through loss-of function (LoF). 1,2,4 In the four patients of the present study, we identified one known nonsense mutation and three novel mutations, two frameshift and interestingly one missense mutation, expanding the mutational spectrum.
The patient carrying the missense variant is similarly affected regarding speech and motor delay as well as cognitive impairment.
This missense mutation likely affects the functionality of QRICH1.
The described missense mutation resides in a conserved region of the     Overall, the observed phenotypes do not seem to correlate with type of mutations or location in the gene (Supplemental Figure 1).
However, the so far small cohort of QRICH1 variant carriers, which include only one missense variant, prevents the study of detailed genotype-phenotype correlation.
This study not only expands the genetic, but also the clinical spectrum for QRICH1-related disorders (Table 1). In accordance with previous observations, our report underlines findings of speech delay, Follow-up of these findings will contribute to better define the potential risk of epilepsy and the necessity for treatment intervention. There is some evidence that in individuals with QRICH1 variants, the skin and the skeletal system might be affected. Two patients presented with congenital nevi, respectively with one large-sized café-aulait spot. there is minimal irregularity of the metaphyseal contour, which is interpreted as normal variation (Figure 2). The most striking finding in this girl was the acceleration of skeletal development, the growth plates of the phalanges were already closed at age 12 years and 4 months, but the skeletal age corresponded to an age of 15 years ( Figure 2). In patient 1, chest X-ray at age 2 years and 7 months showed that the metaphyses of the proximal humerus and the costochondral junction of the ribs were normal. Patient 3 had an X-ray of the chest at the age of 3 months and an examination of the pelvis at the age of 4 years. Both examinations show normal metaphyses.
Unfortunately, patient 4 could not provide X-ray examinations. In summary, we could not confirm findings of Lui et al. in our reported patients. 1 In conclusion, the present study generated novel insights into the mutational and phenotypical landscape of VBS. This study contributes to the delineation of the phenotype, which comprises key symptoms, such as, expressive speech delay and notable social behavior deficits.
At the same time, it demonstrates the broad phenotypic spectrum associated with QRICH1-associated disorders. Enlargement of QRICH1 cohorts is prerequisite to learn in more detail about the range of clinical manifestations and genotype-phenotype correlations in this developmental disorder.