Microcephaly, dysmorphic features, corneal dystrophy, hairy nipples, underdeveloped labioscrotal folds, and small cerebellum in four patients

Prostatic metaplasia and pilar differentiation in gender-affirming mastectomy specimens

With the increasing practice of gender-affirming mastectomy as a therapeutic procedure in the setting of gender dysphoria, there has come a profusion of literature on the pathologic findings within these specimens. Findings reported in over 1500 patients have not included either prostatic metaplasia or pilar metaplasia of breast epithelium. We encountered both of these findings in the course of routine surgical pathology practice and therefore aimed to analyze these index cases together with a retrospective cohort to determine the prevalence, anatomic distribution, pathologic features, and associated clinical findings of prostatic metaplasia and pilar metaplasia in the setting of gender-affirming mastectomy. In addition to the 2 index cases, 20 additional archival gender-affirming mastectomy specimens were studied. Before mastectomies, all but 1 patient received testosterone cypionate, 6/22 patients received norethindrone, and 21/22 practiced breast binding. Prostatic metaplasia, characterized by glandular proliferation along the basal layer of epithelium in breast ducts, and in one case, within lobules, was seen in 18/22 specimens; 4/22 showed pilar metaplasia, consisting of hair shafts located within breast ducts, associated with squamoid metaplasia resembling hair matriceal differentiation. By immunohistochemistry, prostatic metaplasia was positive for PSA in 16/20 cases and positive for NKX3.1 in 15/20 cases. Forty-three reduction mammoplasty control cases showed no pilar metaplasia and no definite prostatic metaplasia, with no PSA and NKX3.1 staining observed. We demonstrate that prostatic metaplasia and pilar metaplasia are strikingly common findings in specimens from female-assigned-at-birth transgender patients undergoing gender-affirming mastectomy. Awareness of these novel entities in the breast is important, to distinguish them from other breast epithelial proliferations and to facilitate accrual of follow-up data for better understanding their natural history.

Clinico-radiological Profile of Children with Pontocerebellar Hypoplasia

Aims and Objectives

Pontocerebellar hypoplasia (PCH) constitutes a heterogeneous group of neurodegenerative/neurodevelopmental disorder of pons and cerebellum with onset in prenatal period. This study aimed to discuss the clinical, radiological profile, and outcome of four infants with PCH attending our center.

Materials and Methods

Data of children with psychomotor retardation seen between January 2015 and December 2015 at neurodevelopmental clinic was retrieved. PCH was defined by clinical and radiological criteria. Clinical features included were delay in attainment of milestones in more than two developmental domains accompanied by severe microcephaly. Radiological evidence of cerebellar volume loss with hypoplasia of pons was included. Patient charts were reviewed for clinical features, neuroimaging, electroencephalography, and biochemical investigations including serum and cerebrospinal lactate. Molecular genetic testing for the common p.A307S mutation in TSEN54 of the cases and their parents were also analyzed.

Results

During this period, 101 children with psychomotor retardation were evaluated at our center. Of the 101, four children were with clinical and radiological evidence of PCH. In addition to psychomotor retardation and severe microcephaly, spasticity, bipyramidal signs, and epileptic spasms were universal in all four children. Three of the four children had optic atrophy and two had sensorineural hearing loss. Severe cerebellar hypoplasia with attenuated pons was seen in all four children. Two children had dragonfly appearance of cerebellum on coronal section. The commonest TSEN54 p.A307S mutation in children and their parents was not detected.

Conclusion

A heightened index of suspicion for PCH is merited in infants with progressive psychomotor retardation and severe microcephaly. Cerebellar hypoplasia with pontine attenuation forms the mainstay of diagnosis of PCH.

MAB21L1 loss of function causes a syndromic neurodevelopmental disorder with distinctive cerebellar, ocular, craniofacial and genital features (COFG syndrome)

BACKGROUND

Putative nucleotidyltransferase MAB21L1 is a member of an evolutionarily well-conserved family of the male abnormal 21 (MAB21)-like proteins. Little is known about the biochemical function of the protein; however, prior studies have shown essential roles for several aspects of embryonic development including the eye, midbrain, neural tube and reproductive organs.

OBJECTIVE

A homozygous truncating variant in MAB21L1 has recently been described in a male affected by intellectual disability, scrotal agenesis, ophthalmological anomalies, cerebellar hypoplasia and facial dysmorphism. We employed a combination of exome sequencing and homozygosity mapping to identify the underlying genetic cause in subjects with similar phenotypic features descending from five unrelated consanguineous families.

RESULTS

We identified four homozygous MAB21L1 loss of function variants (p.Glu281fs*20, p.Arg287Glufs*14 p.Tyr280* and p.Ser93Serfs*48) and one missense variant (p.Gln233Pro) in 10 affected individuals from 5 consanguineous families with a distinctive autosomal recessive neurodevelopmental syndrome. Cardinal features of this syndrome include a characteristic facial gestalt, corneal dystrophy, hairy nipples, underdeveloped labioscrotal folds and scrotum/scrotal agenesis as well as cerebellar hypoplasia with ataxia and variable microcephaly.

CONCLUSION

This report defines an ultrarare but clinically recognisable Cerebello-Oculo-Facio-Genital syndrome associated with recessive MAB21L1 variants. Additionally, our findings further support the critical role of MAB21L1 in cerebellum, lens, genitalia and as craniofacial morphogenesis.

Autosomal recessive truncating MAB21L1 mutation associated with a syndromic scrotal agenesis

We report on a boy with a rare malformative association of scrotum agenesis, ophthalmological anomalies, cerebellar malformation, facial dysmorphism and global development delay. The reported patient was carrying a homozygous frameshift in MAB21L1 detected by whole-exome sequencing, considered as the most likely disease-causing variant. Mab21l1 knockout mice present a strikingly similar malformative association of ophthalmological malformations of the anterior chamber and preputial glands hypoplasia. We hypothesize that MAB21L1 haploinsufficiency cause a previously undescribed syndrome with scrotal agenesis, ophthalmological anomalies, facial dysmorphism and gross psychomotor delay as remarkable hallmarks. Four cases from the literature were reported with features suggestive of a similar and recognizable clinical entity. We hypothesize that MAB21L1 should be the culprit gene in these patients.